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[FAQ] Aquaria: Food


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                                FAQ: LIVE FOOD
                                       
contributed by Oleg Kiselev, Don Wilson, and Steve Bartling

   The advantages of live foods over frozen and prepared foods are:
    1. the uneaten food will not immediately decay and load up the
       filtration system,
    2. foods can be raised in controlled conditions and be free of
       pathogenic (disease causing) bacteria
    3. by using inexpensive media and techniques, costs are minimized,
       and
    4. most importantly, fish love grabbing things that try to run away
       (plus, fish owners love watching their fish chase live food).
       
   Here are some live foods the aquarist can easily culture at home, to
   the extent that some people on the NET have had experience with them.
   
Copyright

   The FAQs owe their existence to the contributors of the net, and as
   such it belongs to the readers of rec.aquaria and alt.aquaria.
   Articles with attributions are copyrighted by their original authors.
   Copies of the FAQs can be made freely, as long as it is distributed at
   no charge, and the disclaimers and the copyright notice are included.
   
Contents:

     * Baby Brine Shrimp
     * Adult Brine Shrimp
     * Cyclops
     * Mosquito Larvae
     * Blackworms
     * Grindal Worms
     * White Worms
     * Earthworms
     * Vinegar Eels
     * Infusoria
     * Microworms
     * Fruit Flies
     * Feeder Fish
       
Baby Brine Shrimp
(Artemia spp., usually A. salina)

   Uses:
          Baby brine shrimp are a food of choice for the newly hatched
          fry of egg-layers and other small fish. They're also eaten
          voraciously by some surprisingly large marine fish and make a
          good substitute macro-plankton for some filter-feeding
          invertebrates.
          
   Culturing:
          To hatch brine shrimp, one needs very little. A hatchery can be
          built out of almost anything, such as 1 gal plastic milk jug to
          12 oz soda bottles. Also, stores sell "shrimpolators" and
          plastic hatching cones. Everything works, but a container with
          a concave or conical bottom is the best because the water flow
          has no dead spots. Add air tubing connected to a small pump,
          put a light over it and keep temperature around 85 degrees if
          the shrimp are to hatch faster.
          
          Ed Warner's book suggests 3.5 table spoons of uniodized salt
          per gallon of water. He suggests using the cheapest salt
          available, like the water softener salt at $3 for 50 lb. SF Bay
          Brand recommends hardening the water to improve hatching and
          shrimp survival, so adding some Epsom salt and a tiny pinch of
          baking soda may be a good idea.
          
          In order for the shrimp to hatch and not die, the water in the
          culture must be vigorously turned over to keep the shrimp in
          suspension. This can be done by aerating the water just like
          everyone else, using a 12 inch length of rigid air tubing
          attached to a 3 inch tail of flexible tubing attached to an air
          pump. The rigid section keeps the hose from slipping out of the
          container. Aquarists using airstones may find that they crud up
          and clog too often in this environment.
          
          To get nauplii (hatched brine shrimp) out, turn off the air,
          put a piece of rigid air (1/8") tubing with 2-3 ft of flex
          tubing attached into the culture, and let the stuff settle. The
          shrimp egg cases will collect on top of the water, the shrimp
          ought to sink to the bottom (if the water is not too saline).
          Then just siphon the wriggling shrimp off into a brine shrimp
          (fine) net, dump the lot into a cup of water and use an eye
          dropper to dispense to the fish.
          
          The nauplii will live in the tank for up to 24 hours.
          
   Sources:
          Eggs can be bought in most aquarium and pet shops or by mail
          order. Eggs bought in bulk (such as 1 lb cans) will be much
          less expensive than the tiny ampoules sold in stores. The cans
          may be held in the freezer, with 2-3 weeks worth of supply held
          in a small, tight-lid jar.
          
          Ed Warner insists that the eggs of brine shrimp need at least a
          year of incubation to become ready to hatch. He goes on to say
          that a low yield from a newly opened can of shrimp eggs may be
          due to insufficient incubation time and that the best hatches
          come from the eggs that had been kept for a few years, with the
          eggs kept for 5 years in a vacuum packed airtight container
          giving perfect 100% hatch rates.
          
Adult Brine Shrimp

   Uses:
          Just about all fish under 5" long will readily eat brine
          shrimp.
          
   Culturing:
          Don't bother. The yields from the cultures are very low and
          it's easier to culture Daphnia and buy live brine shrimp in the
          pet shops.
          
          Those who REALLY want to try to culture brine shrimp should get
          a large open top container (an aquarium, a garden tub, a baby
          wading pool), fill it with real or synthetic salt water and
          seed it with some green water and nutrients (fertilizer tabs or
          what have you) and wait for the water to turn yellow-green.
          Throw in some baby brine shrimp or live adult shrimp (available
          from the pet shop) and wait. Adding small amounts of brewers
          yeast, APR and other micro-foods will help promote the shrimp
          growth. It helps to put the culture in a brightly indirectly
          lit place to promote microalgae growth.
          
   Sources:
          See above.
          
Daphnia

   Uses:
          Daphnia (also known as "water fleas") are tiny crustaceans of
          Daphnia pulex and D. magna spp. They are probably the most
          ideal food for the smaller fresh water -- Daphnia do not die in
          the tank and will eat microscopic garbage while they live. They
          come in a variety of sizes -- from hardly visible to over 1/8".
          This is a typical source of food for many fish in the wild.
          
   Culturing:
          Daphnia can be cultured in everything from betta bowls to 32
          gal trash cans. Indoor cultures can be fed various algae
          scrapings and tank sludge, as well as deactivated brewers
          yeast, powdered milk and APR (artificial plankton stuff from
          OSI). The best food to use is green water, and can be used in
          outdoor cultures. Green water can be grown using a weak
          solution of Miracle Grow and chelated iron in dechlorinated
          water, seeded with "pea soup" water. If water full of nutrients
          is left out in full sun, within weeks it will turn green from
          the airborne algae spores.
          
          Blender-pulverized lettuce is rumored to work well in small
          amounts.
          
          Fry tanks and bowls can be seeded with Daphnia -- the Daphnia
          eat the bacteria that may be hazardous to the fry and generally
          purify water and the fry will eat them as they get larger.
          
          Freshly hatched fry can also be added directly into Daphnia
          cultures (about 2 fry/liter) and will feed at their leisure.
          However, fry kept in equivalent sized tanks and fed more
          intensively grow faster.
          
          A shrimp net or a fine fish net can be used to catch Daphnia.
          
   Sources:
          A clean Daphnia culture may be obtained from a local aquarium
          club or mail order.
          
          Daphnia can also be gathered from local lakes with a plankton
          net. An inexpensive net can be constructed by the
          do-it-yourself aquarist. Sew a conical fine mesh net with
          something like sheer curtain material, and attach it to a
          circular piece of wire (such as a clothes hanger, bent into a
          circle). Add some weights to one side of the wire frame and
          hang it from a three string harness. The net can then be slowly
          dragged behind a canoe or rowboat in a lake known to contain
          Daphnia. The wire frame will keep the mouth open, and the
          weights will act like the tail of a kite, to keep the net from
          rotating when it is dragged. Such as setup can be remarkably
          productive, but the aquarist must beware of parasites like
          Hydra and various carnivorous insects, like glass worms.
          Capturing glass worms are a mixed blessing, because larger fish
          will happily eat them, but the glass worms will also eat fry,
          if present.
          
Cyclops

   Uses:
          Same as Daphnia, but predatory. Can damage eggs and very young
          egg-layer fry. Nauplii can be used like brine shrimp nauplii.
          
   Culturing:
          As Daphnia (but less numerous per the same volume).
          
   Sources:
          Often comes with the culture of worms or as contaminants in
          Daphnia cultures. Very hard to eradicate once they start
          breeding in the tank. Also mail order and club auctions, as
          Daphnia.
          
Mosquito Larvae

   Uses:
          Most adult fish of smaller species love them. As long as fish
          are bigger than the larvae, they'll eat them. Aquatic larvae of
          flying insects is the main ingredient in the diet of many small
          fish in the wild.
          
   Culturing:
          Very simple. Put a wide-mouth bucket or a barrel or a tub of
          water outside. Throw in small amounts of evaporated milk or
          grass clippings in a nylon bag to seed the water with bacteria
          and promote the growth of infusoria, mosquito larvae's food
          sources; green water works well, too. Some people even use
          manure! If there are mosquitoes in the area, 2-3 weeks later
          there will be larva in the water.
          
          Another means of culturing is to use a child's wading pool with
          a small amount of grass clippings (no herbicides, please) added
          to encourage the water to stagnate, then wait for the
          mosquitoes to breed in it. After a couple of weeks, large
          numbers of larva can scooped up with a coarse fish net. In this
          sort of "wild culture", one must sneak up on the pool to net
          them, so that the larvae don't dive to the bottom when they
          detect movement.
          
          Other methods include filling a one gallon bucket with garden
          pond water (tap water takes too long to age!), then adding a
          cup or two of fine soil and allow it to sit for a few days.
          After the larvae begin to appear, one may use a large aquarium
          net to strain the water into another bucket, thus capturing the
          mosquito larvae that are now present.
          
          A major problem with these techniques is that the neighbours
          make take exception to mosquitos being cultured. However,
          provided all the larvae can be captured and used, an optimist
          might see it as a means of population control since the
          mosquitoes are no longer breeding in a pond somewhere where all
          control is lost.
          
          Another problem is that if one adds too many larvae and the
          fish don't eat them all, there may be a significant increase in
          the mosquito population in your house, as the uneaten larvae
          pupate, then develop into mosquitoes.
          
   Sources:
          Wait for the little bloodsuckers to discover the container of
          evil-smelling bacterial soup (=culture), or go find "floats" of
          mosquito eggs in a nearby lake or puddle. They look like rafts
          of eggs, all glued together.
          
Black Worms

   Uses:
          These disgusting, bacteria-infested stinkers are among the best
          sources of protein for the fish and are an excellent
          conditioning food for breeding preparation.
          
          WARNING: frequent feedings will cause the fish to become fat
          and impair breeding. Also, diseases are far more likely on a
          steady diet of worms.
          
          ANOTHER WARNING: if too many worms are fed to the fish at one
          time, the worms will burrow into the gravel and hide, risking
          fouling the tank.
          
   Culturing:
          May not be worth it. Worms will live on the bottom of a tank,
          eating scum and breeding. They can be fed banana peels. Filter
          water intensively. Collect them by sieving gravel with worms
          through a net. Messy, laborious and there are easier sources of
          protein.
          
   Sources:
          Most aquarium shops have these uglies.
          
          (Tubifex are even uglier and stinkier and the aquarist should
          not attempt to raise them. It is possible, but consider -- they
          live and feed in sewage and may carry hepatitis or other
          potential pathogens.) If one buys tubifex, it is reported that
          since it is their, uh, "food" that smells, not the worms
          themselves, they may be successfully kept in cold running water
          without producing odour. Alternatively, 2 oz. of worms can be
          kept for up to three days in a medium sized bucket of cold
          water in a fridge).
          
Grindal Worms (very small worms)

   Uses:
          These worms are small (up to 1/2") and can be fed to a variety
          of small fishes. Because of the way they are raised, they are
          totally disease free. They do not burrow as readily as other
          worms and live in the water for a few days. Great for bottom
          feeders and any fish fast enough to grab food sinking to the
          bottom or smart enough to look for it (i.e. just about all
          fish).
          
   Culturing:
          Get a plastic shoe box (available at Target on sale for $1),
          fill it with sterile potting soil and peat moss mix (50-50), or
          just potting soil, get it moist, perhaps nuke it in the
          microwave oven for 5 minutes to thoroughly sterilize it, let it
          cool, inoculate with a small starter culture of worms and add
          some high protein cereal powder (Gerber, for instance) every
          time the previous feed disappears -- and watch them breed!
          Cultures should be kept at 70 F or warmer. Put a piece of glass
          on the soil and the worms will crawl on it. The worms can be
          washed off the glass into a cup with clean water and dispensed
          into the tank with a large medicine dropper (1 tsp). If food is
          placed in troughs in the soil, the glass will be free of
          potentially water-clouding soil. One healthy culture produces
          enough to feed about 100 small fish.
          
          Remember to keep the culture moist but not soaked and soupy.
          Spray it with dechlorinated water now and then.
          
          Cultures like this often get over-run with mites and/or gnats.
          Both pests can be fed to the fish and are readily eaten, but
          soon become a nuisance. Should this happen, take some worms and
          keep them in a cup of water for 3-4 hours. This will drown the
          infestation and the worms can be used as a new starter culture.
          Old infested cultures can be salvaged, but it may not be worth
          the effort.
          
          If the worms are not growing well, try adjusting the soil's pH
          by mixing a bit of baking soda into it to neutralize the peat's
          acidity.
          
          An interesting technique of culturing worms is used by some
          German killi breeders. They use open-celled foam that sits in a
          tray filled with water and is covered by a piece of glass. This
          method is cleaner than the soil/peat one.
          
   Sources:
          Friends, local aquarium clubs and mail order.
          
White Worms (small worms, related to earthworms)

   Uses:
          These worms are up to 1" long and are good for feeding fish
          3"-6" long.
          
   Culturing:
          Similar to Grindal worms, but these worms do not do well at
          high temperatures. If possible, keep them below 70F; during the
          summer, they will survive if kept moist and in a cool place,
          i.e. a north facing carport. White worms can be grown in
          potting soil in plywood boxes, about 16" x 12" x 6" deep, with
          a close fitting, moisture-resistant top such as a sheet of
          glass. They will eat the same foods as Grindal worms, but a
          number of sources suggest that white bread soaked in milk is a
          very good food for these worms. Another option found to work
          extremely well is to raid the materials heading for the
          compost, and prepare a mixture of old lettuce, fruit, and bread
          crumbs or oatmeal. Add water and blend it, as thick as the
          blender can handle, and still be able to turn over this soup.
          Add maybe a cup each week (it's mostly water anyway, which is
          needed to keep the cultures moist), in a small trench dug down
          the center of the dirt.
          
          The medium typically and most successfully used by one of us
          (DW) is dried, rehydrated bread crumbs with some brewers yeast
          added. Bread crumbs are prepared by collecting old crusts (even
          moldy ones) and storing them in your freezer, then drying them
          in the oven at 175F. The bread is then crushed into into crumbs
          and, if stored in sealed containers (such as plastic ice cream
          buckets) the crumbs will last forever. When it is time to feed
          the worms, use a large bowl and mix the powdered bread with
          enough water to make a slurry, then ladle it into a trench in
          the culture. Use only as much as the worms will eat in a week.
          The amount of water in the slurry should be varied - when the
          worm culture tends to dry out in the summer months, use a
          wetter mixture to replace the water but if the culture is
          already too moist, use a drier mixture.
          
          One might ask how long such a culture will last before going
          sour. It is a good question, to which there is no clear answer
          yet; one of use (DW) has 3+ year old cultures which have been
          seen to produce as strongly as ever, without odour.
          
          Keep these worms in complete darkness. They will come out of
          the soil and coat the food, devouring it shortly and clustering
          in a writhing mass. The aquarist can pluck this mass of worms
          from the soil and use it to feed the fish. The worms will hide
          in the soil as soon as the light strikes them, so be swift
          about grabbing them! Another means of separating worms from the
          dirt is to get a tin can with both ends removed and fasten a
          piece of plastic window screening over one end (with string, an
          elastic band, or whatever works). Sit it in some type of
          tapered glass container (such as a measuring cup) with water in
          the container, so the can sits above the water (1/2" between
          the top of the water and bottom of the mesh). Place some of the
          soil and worm mixture in the can and place a light over top
          (i.e. a gooseneck lamp, with one of those mini-spot bulbs). The
          heat will drive the worms out, through the mesh, and into the
          water. This takes a couple of hours or more. The worms come out
          clean, and can be fed to the fish directly, placed in a worm
          feeder, or frozen for future use. This works well for white
          worms, large and small, so assuming Grindal worms can be grown
          in soil, it should work for them, too.
          
          However, if you don't mind getting your hands dirty, a faster,
          more effective means of separating them is to put the worm
          laden dirt into a container, add water, swirl the mixture, then
          pour out the dirt. The worms will collect in knots. Remove the
          knots by hand to another container, then continuing to swirl
          and pour off the dirt in both the old container and the new
          one. This way, clean worms can be obtained within minutes.
          
          Whiteworms should be fed to your fish with a worm feeder, so
          that the fish can eat them over time. They can be also be
          placed directly into a bowl on the bottom of the tank, where
          they will remain until the fish eat them. This may apparently
          be particularly useful for killifish breeders, which have only
          peat as a substrate. Be careful not to overfeed by adding
          whiteworms directly to the tank; the excess will burrow into
          the sand, where they will be inaccessible to all but the most
          eager diggers, such as Hoplosternum. Where the aquarist has
          separated too many worms for one day's feeding, the remainder
          should be promptly frozen and used later.
          
   Sources:
          same as Grindals.
          
Earthworms

   Uses:
          Feeding of medium and large fish (over 4" long).
          
   Culturing:
          To raise earthworms cheaply and easily:
          
         1. Build a box out of wood (any size is fine, a bigger box =
            more worms) (apartment dwellers can make do with a 1' x 1' x
            8" box)
              1. Attach the top with two cheap hinges.
              2. Drill/cut two 2-inch holes in the front of the box in
                 such a way as to line up the bottom of the hole with the
                 bottom of the inside of the box
              3. Paint the box with any outdoor rated, oil based paint.
              4. Place a small piece of fine plastic screen against holes
                 that were drilled/cut. Make sure the screen is placed on
                 the inside of the box. Firmly nail the screen into
                 place. The screen will allow the box to drain, but will
                 not allow the worms to escape.
            The box is now complete.
         2. prepare the box for worms
              1. Buy enough peat moss from a garden supply store or
                 nursery to fill up the box (remember the peat moss will
                 compact after it gets soaking wet).
              2. Place the peat moss in the box and completely soak the
                 peat moss (stir it up until it is uniformly wet).
              3. Get 6 bricks.
              4. Place one brick at each front corner and two bricks at
                 each rear corner so that the box slopes forward and can
                 drain from the holes.
              5. Place a pan under the holes to catch the future runoff
                 (unless the box is placed outside). Note, after worms
                 are growing, the runoff is great for plants.
         3. Now, for the worms
              1. Go buy three or four boxes of the smallest worms that
                 can be found at a fish and tackle shop.
              2. Put the worms in the box
              3. Buy some corn meal (a small bag will last forever). This
                 is all the worms need for adequate nutrition.
              4. Every three or four days, sprinkle a light layer of corn
                 meal on top of the peat moss. Note: before each new
                 layer is applied, use a small, tined garden hand tool to
                 stir up the peat moss and to mix the corn meal left over
                 from the previous feeding into the peat moss.
              5. After about a month, there will be literally millions of
                 worms ranging in size from tiny little young worms to
                 fully adult worms. The baby worms can be used for small
                 fish and very young fish, while the larger worms will
                 easily satisfy the live food requirements of even the
                 most ravenous large fish.
              6. This is an infinitely renewable resource, which is
                 difficult to overharvest!
              7. The peat moss must be kept damp by periodic watering.
                 Don't over water! Do not allow it to dry out! The worms
                 will die QUICKLY if the peat moss dries out.
                 Fortunately, peat moss retains water very well, and
                 watering is rarely needed.
              8. The worms must not be allowed to freeze. The worms and
                 the worm box will not smell and can be kept in garages
                 or closets during the winter. The worms do not like
                 being baked in the full evening sun in the summer (they
                 will be killed). Place them in a shady location if they
                 are left outside.
              9. keep the lid closed, worms like it dark.
         4. Other uses for Earthworms--
              1. Potted plants love earthworms!!
              2. Gardens love earthworms!!
              3. Lawns love earthworms!!
            
   Sources:
          the backyard, bait shops, gardening shops, gardens, aquarium
          clubs.
          
Infusoria (microscopic aquatic protozoans)

   Uses:
          Feeding of newly hatched fry.
          
   Culturing:
          Starting with a culture of green or pond water, add plant
          material such as lettuce, alfalfa pellets, etc. to your culture
          container. Good results have been found with boiled vegetation,
          which appears to break down more quickly. When the plant
          material begins to decay, bacteria will initially appear, then
          the protozoa will quickly increase in number as they feed on
          the bacteria. Note that new cultures may contain largely
          bacteria, not infusoria. If the infusoria culture is vigorously
          aerated, odour will be minimized. If the aquarist intends to
          maintain the culture over an extended period, every 3 - 4 days
          one must siphon out the "expired" organic material which
          settles to the bottom and discard it, then replace it with new
          culture media. Optimum culture size depends on how much
          infusoria is needed. One of us (DW) uses a spare 15 gallon
          tank, which can produce prodigious amounts of infusoria.
          
          An effective means of concentrating the culture before use is
          to turn off the aerator, then place a small spot lamp beside
          the culture container and let the culture settle. Within 15
          minutes, the infusoria will begin to form shimmering clouds
          around the light or they may form a distinct whitish layer in
          the water, often just below the surface. One may be able to see
          minuscule silvery bits of "dust", moving distinctly and
          purposefully through the water. The infusoria concentrations
          may then be selectively siphoned out and added to the fry
          tank..
          
   Sources:
          Old tank water (especially out of the filter), friends, mail
          order
          
Vinegar Eels (Turbatrix aceti aka Anguillula silusiae)

   Information provided by Greg Frazier
   
   Uses:
          Food for very small fry, i.e., those that are too small to take
          baby brine shrimp (e.g., Rams)
          
   Culturing:
          Vinegar eels are small nematodes found in unpasturized cider
          vinegar. They live in acidic water and feed on bacteria in
          fermenting vinegar. They can survive for extended periods of
          time in alkaline water (including tank water!), but they will
          not reproduce. As a food for fry, they are extremely easy to
          culture, require very little attention or care (i.e., they can
          be ignored for months at a time), and can be harvested at a
          moments notice. Hold a starter culture up to the light, to be
          able to see the worms wriggling in the cider/water mix.
          
          To culture vinegar eels, one needs a container (a 1 gallon
          jug/jar/pitcher with a mouth wide enough to stick one's hand
          through works well), an apple, cider vinegar and water. Smaller
          containers should work OK, but a 1 gallon container provides
          more than enough eels for everything short of a professional
          hatchery. The cider can be cut by up to 50% with water, but not
          more than that. Drop some (peeled) apple cubes into the pitcher
          (one only needs a handful of 1" cubes for a 1 gallon culture),
          and fill it up with vinegar + water (again, no more than 50%
          water). Put half of the starter into the culture. Wait at least
          24 hrs to give the bacteria time to get a foothold, and then
          put the second half of the starter into the pitcher. In about a
          month, a cup dipped into the pitcher should come out cloudy
          with wriggling worms. When the mixture starts looking really
          cruddy (e.g., 1/2 inch of stuff has accumulated on the bottom;
          this should take months) re-culture and start again.
          
          Harvest the eels with two cups and a coffee filter. Dip one cup
          into the culture, pour it through the filter into the other
          cup, and return the liquid to the culture. Most of the eels
          will have passed through the filter, but some will have clung
          to it. Pour fresh water though the filter, then invert the
          filter and flush the worms into a glass. A filter paper
          (available at some drug stores) may also be used. Filter paper
          will prevent any eels from getting through, but it also takes
          quite a while (10 minutes or longer) for the vinegar get
          through as well.
          
          Let the worms purge themselves in the glass for a while before
          feeding them to the fry. Also, be careful to rinse the eels
          well -- adding vinegar to a small fry hatchery could lower the
          pH suddenly (with disastrous consequences!). Vinegar eels are
          longer than brine shrimp nauplii, but have a smaller diameter -
          fish can handle vinegar eels before they can handle freshly
          hatched brine shrimp. In a tank the worms will flow with any
          current, but if there is no current they will work their way up
          to the surface (a big advantage over microworms).
          
   Sources:
          Mail order, aquarium clubs, etc..
          
Microworms (Nematodes)

   Uses:
          These microscopic worms are good for feeding newly hatched fry
          and the smallest fish, although fish up to 1" or more will eat
          them.
          
   Culturing:
          Good culture media include Oatmeal pablum, Gerber high-protein
          cereal or cooked oatmeal porridge. The oatmeal porridge is
          inexpensive and is the media of choice of one of us (DW). All
          media should be prepared so that it is thick, then added to a
          dish so that it is from 1.5 cm. deep or more. Add at least 1
          tsp. (5 ml) of deactivated brewers yeast (can be bought from
          health food stores); the cultures do not do well without the
          brewers yeast. Seed with a small quantity of the nematodes. If
          you are subculturing from an existing culture, just use the top
          1/8" of the old culture; that's where all the worms are. Your
          new culture will be encouraged by initially storing it in a
          warm area (such as the top of a tank).
          
          They can be cultured in 500 ml. yogurt containers, made out of
          type "5" plastic (the type of plastic will be marked in the
          recycling information on the bottom). This material is fairly
          thick, flexible, and cheap, and the micro-structure of the
          surface seems to be such that the worms can crawl up the sides
          in thick enough concentrations that they can be wiped off and
          collected. The thinner, more brittle plastic containers work
          very poorly - the worms do not thrive, and they can't seem to
          climb up the sides. Cut a hole, perhaps, 3/4" wide in the lid
          to provide air, and if the cultures are piled several cultures
          high, ensure the containers are rotated so that all cultures
          are exposed to the air at least every second day. If this is
          not done, the cultures will die off. Cultures can be grown in
          the house, and as many as 24 containers still make up a
          compact, but very productive source of live food.
          
          In about a week, microworms can be "harvested" off the sides of
          the dish with a finger (the best way), a Q-tip or a brush.
          Optionally, once can place a flat piece of plastic or wood onto
          the culture and scrape the worms off with a razor when they
          become numerous (a popsicle can be used stick as this
          "collection platform"). Wash them out in a glass of clean water
          and dump them into the tank, or place them directly in the
          tank.
          
          Cultures will last about 2 weeks. As long as the culture media
          is fairly fresh, there will not be any offensive odours
          produced but when the the odour increases and production
          decreases, it is time to subculture.
          
          One can extend the time it takes for the microworms to be
          passed into the tank by placing them in a worm feeder stuffed
          with filter floss.
          
   Sources:
          friends, clubs, mail order.
          
Wingless Fruit flies (Drosophila species)

   Uses:
          The fruit flies are the closest analog to the natural diet for
          most killifish and many other small fish.
          
   Culturing:
          1/2 gal fruit juice bottles can be used as culture containers.
          The media is a mail order instant mush that seems to be some
          sort of instant mashed potatoes substance that smells like pure
          starch mixed with fungicides. Use enough to get a 1/4-1/2"
          layer of media at the bottom of the bottle and add enough water
          to get it to a sour cream-like consistency. It should be dense
          enough to not run when the bottle is tilted. Next, place a 2
          layer roll of plastic "bug screen" mesh into the bottle, so the
          flies and maggots have somewhere to climb out of the wet goo --
          it seems to help their survival. Dump in a few fruit flies,
          perhaps a dozen. Finally, stopper the bottle with a wad of
          filter floss, so the flies can't get out and wild fruit flies
          and other critters can't get in.
          
          Two weeks later there will be newly hatched fruit flies ready
          to be fed to the fish. The culture keeps producing for 2 months
          or so and should be "cloned" after some 6 weeks of operation.
          When the previously cream-colored media become dark and "used
          up" looking, it's time for the new culture. It's probably
          easier and safer to clone the culture every 4-6 weeks and be
          ready for the eventual crash of the old culture.
          
          To feed the fish, sharply shake the bottle to knock the flies
          away from the stopper, open a fish tank cover, open the bottle,
          turn it up side down and give it a few taps, shaking out a
          dozen or more flies every shake. The media gets thick enough by
          then to not drip out.
          
          CAUTION! These flies are wingless and flightless, but not
          legless. They will walk up the sides of the tank, crawl out
          through the cracks and head straight for the fruit which has
          been left out in the kitchen. They may be fish food, but they
          are still fruit flies. Feed them to fish in small doses.
          
          There are several different strains of usable fruit flies. Some
          are smaller than 1/8", others are over 3/16". Some are
          completely wingless or have vestigial stubby wings (wingless),
          others have the wings that are so large that they are useless
          (flightless).
          
          CAUTION! The "wingless" fruit flies will sprout functional
          wings if they are kept at high temperatures, so keep the
          culture cool. If this becomes a problem, open the jar outdoors,
          let the winged flies fly away, then make sure the rest pupate
          at a cooler temperature.
          
          HINT: a jar of Drosophila can be chilled in a refrigerator for
          a few minutes to make them sluggish and/or immobile. This makes
          them lots easier to handle when a new batch is being bred, and
          also makes them less likely to wander off. The fish might
          prefer them to be more active, though.
          
Feeder Fish

   Uses:
          Several large fish, including cichlids and piranhas will eat
          live fish as part of their diet.
          
   Culturing:
          Generally not necessary. Many fish stores stock offer
          inexpensive "feeder guppies" or "feeder goldfish" as part of
          their ordinary stock. However, a colony of prolific cichlids,
          such as convicts, can practically be used as a source of feeder
          fry. For fish like piranhas, a small piece of raw chicken or a
          strip of fish fillet will work just as well as a live fish.
          
   Sources:
          Pet stores; excess brood stock; deformed "culls".
          

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