Fish Food, For Dummies
by Grant Gussie, CAS
Originally published in The Calquarium Volume 41, Number 2, October 1998
Aquarticles
Fish need food. Otherwise they starve. Simple enough. But like you and me, fish also
require that a necessary list of nutrients be in their food or they will slowly grow ill,
and then will die. So how do you give your fish adequate nutrition?
Well, thankfully, it is not hard. We have so many very high quality flake foods and
freeze-dried foods that fish can be adequately nourished with very little fuss and bother.
You may read articles where it is stated categorically that flake foods do not make an
adequate diet for any fish, but this assertion has long been disproved by the hordes of
aquarists that feed flake foods exclusively, and still maintain colorful, breeding,
vibrant fishes. So why not end this article here? Well, it’s not that simple. Just
because most aquarium fish will thrive on a good flake food, that doesn’t mean they
all will and it certainly doesn’t mean that all flake foods are good. And of course,
flake food is boring. Boring for you to feed, and probably boring for the fish to eat.
Boring. This is a hobby right? It’s supposed to be fun, right? Well why not get some
fun out of meal times then? So I’ll talk about live and homemade foods too.
FLAKE FOODS
But first of all, the flake foods. Aquarian®, Tetra®, and Wardley® are all
recommended brands. There are some other brands that are pretty good but these three are
the most widely available. As a general rule of thumb, if a flake food is for sale in a
reputable pet store, it will be pretty good. If you buy it at Walmart® however, you are
taking your chances. Department store flake foods tend to have a small list of inexpensive
ingredients and a lot of white wheat flour filler. One particularly bad brand that you
should avoid has a red label and a name that starts with H and is a homonym for your
primary circularity organ (hopefully that’s sufficiently obscure that they won’t
sue us for defamation).
Wardley is the least expensive of the recommended brands and is also available in bulk,
but the Wardley brand name lacks the range of "specialty flakes" that Aquarian
and Tetra offer. As far as these specialty flakes go, the only one I have any use for are
the "green" flakes that are high in vegetable matter. Most of these vegetable
flakes contain Spirulina, which is a photosynthetic cyanobacterium (so Spirulina
is not an alga as is generally assumed). Spirulina is quite high in protein
and a great source of many amino acids that are otherwise difficult to acquire. Health
food stores are full of the stuff. Spirulina flakes are just what you need for
mollies and a host of other vegetarian fishes. Aquarian and Tetra also offer Spirulina
enriched wafers that sink, which are very good for algae-eating bottom feeders like
plecos.
The various other flake foods, like "carnivore flakes", "color
flakes", etc. are in my humble opinion more useful as marketing strategies than as
dietary supplements. Feel free to purchase a variety of flakes, but all good flake foods
are heterogeneous mixtures of ingredients and supply complete nutrition on their own.
FREEZE-DRIED FOODS
Aquarium stores also sell freeze-dried foods. These differ from flake foods in that
they usually have only a single animal-ingredient each ( e.g. mosquito larvae, blood
worms, tubifex worms etc.) and they are usually in the form of chunks or as individual
organisms, rather than flakes. These foods are not in themselves complete diets, but they
can be part a well-rounded diet consisting of a good basic flake food, a Spirulina-enriched
flake food, and several types of freeze-dried foods.
Almost all of the organisms that are freeze-dried and sold for aquarium use can be
found as either living or frozen foods as will be discussed below, but in the freeze-dried
form they provide a convenience of storing and feeding that frozen or living foods can not
match. Feel free to purchase freeze-dried foods if you are unwilling to devote freezer
space to frozen foods or to go through the significant bother of dealing with live foods.
FEEDING
The next thing to know about dried foods is how much to feed. Unless you want your fish
to spawn or are raising their babies, don’t feed much at all. Fish are cold blooded,
and therefore do not require food energy to maintain their body temperatures. They also
are neutrally buoyant and so they don’t require any energy to stand up. As a result,
fish can get by on remarkably little food.
The rule of thumb to feed all the fish can eat in five minutes twice a day is a good
one, provided that all of the fish are actually getting some of the food. This isn’t
a problem with schooling fish, but a territorial fish like a cichlid can monopolize a food
supply. Most aquarists therefore end up feeding a cichlid aquarium more than the
recommended amount, and so they must deal with the high nitrate levels, algae growth, and
unwanted breeding that comes with overfed fish. This is just part of the deal when you
raise cichlids. But schooling fish can be fed quite sparingly because they will feed as a
school rather than competitively. The concentration of their wastes can therefore be kept
to a minimum, thus giving you a healthy, easily maintained, and more enjoyable tank.
Then there are the bottom feeders, like loaches and catfishes. What about them? If you
feed according to the recommended five-minute rule, your bottom feeders won’t get
much to eat. Starvation is consequently one major cause of failure with catfishes, and
over feeding in attempt to "make sure the catfish gets some" is another. In
practice, however, things are not that bad and catfish can generally find enough to eat
(remember fish need very little food). If you have a lot of catfish however, you should
take advantage of the fact that most bottom dwellers are nocturnal and supply some sinking
wafers when the lights go out. Make sure that this food is gone by morning. By feeding
extra at night you are however walking a fine line between adequately feeding your fish
and over feeding your fish. So be careful.
HOME MADE FOODS
As I mentioned before, you may eventually get bored of feeding your fish just flakes.
Or the financial realities of purchasing flake foods (yes, you do pay for their
convenience) may make you look for less expensive alternatives.
A less expensive alternative to flake food is homemade food. If you like to cook, this
can also be fun, although to be honest I tend to think of making your own fish food as a
bit of a smelly chore. Thankfully, it is easy to make and freeze enough to last you a good
six months or more so you don’t need to put yourself through it very often.
Before your start, get yourself a food processor. Then you can make any one of the
various recipes that are kicking around. Most of these recipes have several things in
common; namely they are bound together by unflavored gelatin and contain whole fish,
vegetable matter, and beef heart. This is my recipe. I food-process several multivitamin
tables (with vitamin C) to dust, then process about ½ kilo of the red meat portion of a
beef heart (cut away from all the fat and connective tissue). Then goes in a good handful
of spinach leaves (no stems), one young whole zucchini, and a few raw carrots. Then the
bulk of the food is added, which is whole fish. The fish I originally used were those
minnows sold as bait, but I have since discovered Shun Fat, an Oriental supermarket in
Forest Lawn (at 3215 17th Ave, SE). Here you can get a wide assortment of frozen sea
foods. Nowadays I buy a kilo of frozen capelin since they are full of nutritious roe. I
also get a frozen ½ kilo bag of something called "shrimp fry". I am not sure
exactly what this is (some form of krill I think) but it’s a lot cheaper than buying
real shrimp, which I would have to do if this wonderful stuff weren’t available. I
also add ½ kilo of mosquito larvae and Daphnia that I had collected myself and
froze previously (see below for a discussion on live food collecting). All the ingredients
are processed to a thick paste. Then a liter of water is added and the mixture is brought
to a low boil to congeal the blood. I then dissolve three large boxes (36 packets) of Knox
unflavored gelatin in a liter of cool water. I mix this liquid into the food (after
it’s cooled a bit) and let the mixture set overnight in the refrigerator. The next
day I split the jelly into two or three-day feeding portions and freeze them separately in
sandwich-sized freezer bags. I keep one freezer bag defrosted in the refrigerator at all
times. My cichlids and turtles love this stuff. It sinks and doesn’t cloud the water
(too much).
VEGETABLE DIETS
Many fish either require vegetable diets or can benefit from them. Most notable for
requiring vegetables are the plecos (South American algae eating catfishes), silver
dollars (vegetarian relatives of the piranha), and mbuna (rock-dwelling cichlids from Lake
Malawi, Africa). These fishes have extraordinarily long guts and will develop
lower-digestive problems if they do not get enough roughage in their diets. These problems
are usually followed by a lethal bacterial infection. Almost all other fish will also
benefit from some vegetable matter as greens contain folic acid and the carotenes that are
needed for the creation of red and yellow pigments. The vegetables in the gelatin food
discussed above are adequate for almost all fish, but plecos and mbuna should really have
some additional plant foods as well. Easiest to provide are slices of par-boiled young
zucchini (par-boiling makes it sink). Romaine lettuce is also useful. Plecos also eat
wood. I’m serious. All plecos should be provided with a nice piece of driftwood for
them to slowly rasp away at and hide under.
COMMERCIAL FROZEN FOODS
Nowadays all good aquarium stores have freezers with frozen fish foods. These include
various mollusks, fish, crustaceans, and aquatic insects. None of them are inexpensive.
Most of them you can make yourself with a food processor and a trip to Shun Fat (see
above), but frozen adult brine shrimp (discussed below) and blood worms (midge larvae) are
more difficult to come by and could be considered for purchase at the pet store.
Blood worms are named because of their red color (it has nothing to do with blood) and
can be collected from local ponds (see below) but never in quantity. They are an excellent
food and highly recommended as a dietary supplement for all fishes.
PURCHASED LIVE FOODS
The live foods sold by local pet stores include feeder guppies and goldfish (discussed
below), live adult brine shrimp (also discussed below), and black worms ( Lumbriculus
variegatus ). Black worms are an annelid worm, related to both the earthworm and the
tubifex worm (Tubifex tubifex). The tubifex worm is another worm that can be
considered along with them since they are essentially identical in their aquarium
characteristics. Both worms are aquatic but are found in very high nutrient bottoms. They
are most often found in open sewers and therefore have a correspondingly bad reputation as
disease carriers. Commercially sold black worms are however byproducts of the trout
hatching industry, and so they are unlikely to give you something nasty like cholera.
Black worms and tubifex worms were mentioned in the June 1998 issue of The Calquarium,
where Steve Ward took a rather dim view on their use. I however have a less pessimistic
opinion on them. I have in the past fed black worms to my cichlids about once every month
or so, and have never seen any bacterial diseases as a result. They are also a very good
food for bottom grubbing fish like Corydoras catfish and elephant noses (Gnathonemus
petersi). In fact, one is hard pressed to keep elephant noses alive at all without a
sand bottom and a steady supply of black worms. Cautions are in order however as black
worms are very high in protein and fat, and so they cause problems if fed too often. The
worms must be stored in the refrigerator with daily changes of cold water.
CULTURED LIVE FOODS
Many live foods can be raised at home, and the culture of lived foods is a huge topic
in its own right. I’ll just mention a few foods and try to direct you to more
information. A good place to start is in the CAS library, which has a book called the Encyclopedia
of Live Foods. This book covers almost all the topics discussed below and several
more.
Some fish (for example the Chaca catfish) are so highly predatory that they
specialize in feeding only upon other fish. For these predatory fishes you have little
choice but to either raise feeder fish yourself or buy them in bulk. Goldfish (Carassius
auratus) are the traditional feeder fish to buy. However, goldfish, while
inexpensive, are a bony fish with tough scales. Only very large fish can handle them. Most
people who raise feeder fish raise guppies (Poecilia reticulata) or some other
livebearer. These are smaller and softer than goldfish and thus more suitable for a wider
range of predators. But guppies aren’t very prolific, casting off only about 30
babies per month per female, so it’s hard to keep enough guppies on hand. Egg
scatters like the Danio species would provide many more offspring per female. Or
a prolific cichlid like the convict ( Archocentrus nigrofasciatum) would produce
nearly as many babies as danios but (being larger at hatching) they would be a lot easier
to raise to an eatable size. Always feed your feeder fish before their final swim so the
predator gets extra nutrients from the food in its prey’s stomach.
Compost worms (Eisenia foetida) are great for larger fishes and can be chopped
up for smaller fishes or processed into a jelly food like that of the recipe given above.
They will also get rid of your vegetable table scraps. Raise them in a compost bin. Learn
more about worms on the Internet at http://www.cityfarmer.org//wormcomp61.html or in
Dwayne Tiede’s July 1998 Calquarium article . Compost worms are available
locally from The Compost Queen (ph. 282-4765).
White worms ( Enchytraeus albidus) can be grown along with your compost worms
as well. These are smaller than compost worms and so are good for smaller fish. The
classic technique to collect white worms is to place a milk-soaked slice of white bread on
top of the compost and leave it overnight. The worms will gather under the bread and can
be scraped off in the morning. More information on white worms is on the Internet at
http://www.badgerstate.com/JAWS/faqs/white.htm White worm starter cultures are often
auctioned at club meetings or they can be mail-ordered from
West Kootenay Tropical Fish Hatcheries PO Box 109, 705 Griffin Avenue Slocan, BC, V0G
2C0 Canada (250) 355 2592 jamstutz@netidea.com http://www.netidea.com/tropical/index.htm
Wingless fruit flies (Drosophila sp .) are another good food source for adult
fish. They are especially suitable for top feeders like archerfish ( Toxotes
jaculatrix ) and African butterfly fish (Pantodon buchholzi). Starter
cultures can be mail-ordered (e.g. from Ward’s Natural Science Establishment, Inc.,
at 1-800-387-7822, http://www.wardsci.com/ ). Raise fruit flies in mayonnaise jars stopped
with a foam rubber plug or covered with a piece of cloth and a rubber band. Dissolve one
teaspoon of molasses and a pinch of baker’s yeast in five tablespoons of water, then
mix in three tablespoons of instant potato flakes. Put the resulting glop into the jar
with ten or so adult flies, cover, and you’ll get a few hundred flies within a couple
of weeks. Learn more about fruit flies at http://www.concentric.net/~worstell/FOOD1.HTM or
in the September 1997 issue of The Calquarium where you will find an article
about them by Doug Forsyth.
Baby brine shrimp (Artemia spp.) are the perfect food for almost all baby
fish, and small adult fish such as tetras as well. Very small fry (like those of most egg
scatterers) can not eat brine shrimp immediately, but larger fry (such as
livebearers’ and most cichlids’) can start out on brine shrimp. Brine shrimp are
hatched in salt water from commercially available dry eggs. They are usually hatched in
some sort of funnel with an airstone at the point of the funnel. An inverted plastic
2-liter pop bottle with the bottom cut off works well. Learn more about brine shrimp at
http://www.rtop.com/features/bs-faq.shtml or check out the Calquarium articles by
Ernie Inglis and Dan Grimbly in the April 1993 and April 1994 issues (respectively). Brine
shrimp eggs are available at local pet stores.
Microworms (nematodes) are another good food for fry, and can be fed to smaller fry
than can brine shrimp. Microworms can be raised in plastic containers on a mixture of corn
meal, water, and baker’s yeast. Learn more at
http://www.access.avernus.com/~angels/microworms.htm or in Paul Price’s Calquarium
article of March 1993. Microworms can be collected from their culture containers with a
Q-tip as they will cling to the sides. Just dip the Q-tip in the aquarium with the baby
fish to feed. Microworms can be acquired at club auctions or from the West Kootenay
Tropical Fish Hatcheries.
Very small fry, like those of tetras and bettas, often have a hard time with even
microworms. To these fry, "infusoria" is often fed (infusoria is an old word for
Protozoa that aquarists still use). In the past raising infusoria was a hit or miss affair
because the techniques all relied on the organisms finding their own way into the culture.
Nowadays, pure Paramecium cultures are available by mail order ( e.g. from
Ward’s Natural Science Establishment, Inc.) and these are much preferred ways to get
a culture going. Grow the paramecia in boiled and cooled water to which a few boiled wheat
seeds and a pinch of brewer’s yeast is added. Small, sterilized plastic containers
can be used to grow them, and a coffee filter can be used to filter them out of their
culture water. A detailed description of Paramecium culture is in The
Calquarium’s June 1996 issue, thanks to Richard Pon, and also at
http://www.zfish.uoregon.edu/zf_info/zfbook/chapt3/3.3.html
COLLECTED LIVE FOODS
It is possible to raise other live foods, but don’t bother. Go out and find some.
It’s more fun. In fact, it can be a lot more fun, for now we are entering the realm
of the bug hunter. For the bug hunt, you will need a large fine-mesh fish net. Preferably
it has a long handle. Bring along a lidded bucket (to fill with pond water) so you can get
your bugs home. A lot of people wear hip or chest waders when hunting, but heck, I just
wear a pair of shorts and some old sneakers and get wet. So obviously this is a job for a
warm day. And be prepared to pick leaches off of yourself afterward.
You also need a good place to hunt. Any of the ponds around Calgary will do, but you
would like one that is accessible without crossing private land or having to scale a
fence. If you must go on private land, always ask permission. Tell the landowner you are
doing a mosquito larva count for the university or something if you are embarrassed by
your own eccentricity.
Local ponds are not supposed to be sprayed with insecticides anymore, but various farm
chemicals might still cause problems. Do not choose a pond near a crop field, but instead
just stick with cow pastures. And if a pond looks like it should have lots of bugs, but
doesn’t, assume something is amiss and rather than hunting hard and long for whatever
bugs that are there, just go onto another pond. The bugs may not be there because of
something in the water that won’t do your fish any good either.
You want a pond with plant life in it, but not one that is so heavily overgrown that it
is difficult to get to the water. Cattle in the neighborhood are a definite asset, because
their droppings fertilize the water and this results in a much more abundant aquatic bug
population.
Other subtleties should be considered when choosing a pond. For example, smaller
ephemeral ponds or water-filled tire tracks (especially in cow pastures) are going to have
lots of mosquito larvae and little else. Not that this is bad though, since mosquito
larvae are one of the very best foods and feeding them to your fish is psychologically
very satisfying. Mosquito ponds usually disappear by mid-summer but they can reappear any
time if we get a good storm. Give the pond a few days after a storm to repopulate before
collecting it. Mosquito larvae are air-breathers and can be easily seen rafting just under
the surface with their tail-snorkels sticking out of the water.
Ephemeral ponds are also likely to have fairy shrimp (Streptocephalus seali).
These look sort of like a larger version of an adult brine shrimp. They make a very good
food but are relatively few and difficult to catch in bulk. Fairy shrimp can be reared in
captivity but the lack of a commercial supply of eggs makes this much less convenient than
rearing brine shrimp. Aquarists are forced to catch the adults and spawn them, which the
adults readily do when their homes dry up. To collect eggs, put the shrimp in an aquarium
and slowly lower the water, then allow the last centimeter or so to dry up on its own.
Learn more about fairy shrimp at http://www.badgerstate.com/JAWS/faqs/fshrimp.htm
Larger, longer-lived ponds are likely to have Daphnia pulex in abundance. Daphnia
are pinkish in color and look like small spheres a couple of millimeters across. Close
inspection shows that they have large black eyes and feathery antennae on their heads. A
pond’s population of Daphnia can change dramatically even over a few days.
When a pond is in a Daphnia bloom (often following the deposition of a fresh cow
pie and a good solid rain), the density of Daphnia can be astounding. But after
the population explodes it will inevitably drop again as the predator population
increases, the water starts to dry up, and the oxygen levels decrease. Daphnia
can be reared on a diet of yeast and finely ground spinach, but they are so easily caught
that most people don’t bother.
Another live food local aquarists can find in abundance is fresh-water shrimp ( Gammarus
lacustris ). These are discussed at the web site
http://www.ualberta.ca/~fwilhelm/gammarus.htm . Gammarus inhabit flowing water
and larger lakes, and are generally found among the stones of a cobbled bottom. In rapidly
flowing streams they can be collected by kicking and shuffling among the stones while
holding a net downstream of your feet, so the shrimps get swept into the net by the
current. They can also be collected by scraping the bottom with the net, but this is wears
out the equipment quickly. Gammarus make good food for larger fish like cichlids,
but they are too large and tough-skinned for smaller fishes. They can also swim remarkably
quickly. Dropping a few Gammarus into a cichlid tank really livens things up.
Other bugs will also end up in your catch, but I never worry about parasites entering
the aquarium with the bugs. The only real problem you are likely to introduce with the
bugs are Hydra, which are a predator of very small fish fry. My tank does have a
few Hydra, but I’ve never lost any fry to them and so I don’t worry
about it. But if you have very small fry or a lot of Hydra, a double dose of
Aquari-sol given on two consecutive days will rid your tank of them, as was discussed in
Birgit McKinnon’s article in the April 1996 issue of The Calquarium. All the
other fry predators (dragonfly nymphs etc.) will be eaten by larger adult fish. When
feeding bugs to small fish, however, screen any large bugs out of the food carefully. This
is most easily done by passing the catch through a wide-mesh fish net, and feeding the
fish whatever passes through it. Pond snails and leaches should be stuck to the sides of
your collecting bucket by the time you get home so they aren’t likely to end up in
your tank. But if you see any, pick them out.
Some of your bugs won’t survive the trip home, depending on how many bugs are in
the collecting bucket’s water. But don’t worry about any die-off. When I get
home I dump the bucket’s contents through the catch net to filter the bugs out of the
pond water. I then quickly rinse the bugs in cold tap water before giving my fish one good
feeding of live bugs. Then I freeze what’s left. I never bother trying to keep a bug
catch alive for more than one feeding.
As far as diseases go, I’ve never seen or heard of any being introduced in this
way so I never worry about them.
So that’s about all you need to know about foods. Have fun feeding!?
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