Specific Fish Diets
by Ruby Bayan
Foremost among the factors to consider in feeding a fish community is the species and the sizes of the various fishes. Additionally, under one specific species, the juvenile will have different dietary needs than the mature and the gravid female.
Another important fact to remember with regards to nutrition is that dietary deficiencies can have adverse effects on the fish, such as stunted growth and susceptibility to illness. Nutritional deficiencies can also lower the fish's immunity to infections.
It is therefore extremely important that you have a good understanding of all your fishes’ dietary requirements. The first place to start is with a discussion on the three specific types of fish: carnivorous (meat- or animal-eating), herbivorous (plant-eating), and omnivore (animal-and-plant-eating).
Carnivorous fish are meat-lovers and you can be sure your aquatic plants are completely safe with them. At the same time, however, you can expect that smaller fish living with them can, and will, mysteriously disappear. If a creature swimming in the water looks like it will fit in a carnivore's mouth, you know that's where it will end up, sooner or later.
Carnivores require as much as 45% of protein in their diets. Without this much "meat" they suffer from severe malnutrition. Although many processed and dry fish foods are spiked with proteins specifically for the meat-eaters, the carnivorous species are happiest when they are fed live foods like worms and larvae. Aside from the nutritional elements they derive from live foods, carnivores find satisfaction in chasing after little wriggly prey — an activity they enjoy in their natural habitat.
For carnivorous fish, these are the recommended foods:
- Mosquito larvae
- Tubifex worms
- Daphnia (Water Flea)
- Shrimps, oysters, clams, crabs, fish, other seafood (kept frozen, then thawed and chopped into bite-size pieces at mealtime)
- Salmon, lean chicken or turkey, beef liver (cooked, never fried, then chopped into bite-size pieces at mealtime)
- Supplements (flakes, pellets, or granules) for additional vitamins and nutrients
Herbivores are grazers. Whether they are fed regularly or not, they will nip at anything that slightly resembles a plant or a patch of algae. In other words, if most of your fishes are plant-eaters, you run the risk of eventually waking up to a badly mutilated aquatic garden.
Many fish keepers choose to decorate their herbivore tanks with plastic foliage, and feed their fish with fresh vegetables at mealtime. This way, they are saved from the aggravation of having to mourn the untimely demise of a rather exotic and flourishing aquarium plant.
Because herbivores have a tendency to graze, they need to be fed often. One trick is to "plant" leafy vegetables, like spinach and lettuce, into the substrate to make them look like swaying plants. Be diligent enough, though, to pull them out before they start to fray and rot in the water.
For herbivores, the recommended foods are:
- Fresh zucchini, cucumber, peas, or potatoes (kept frozen, then hand-chopped into bite-size pieces at mealtime)
- Romaine lettuce, spinach, Swiss Chard (planted whole or cut into small pieces)
- Vegetable flakes
- Algae tablets
Omnivores are the easiest to feed because they are scavengers that eat practically anything edible. This also means that both the plants and smaller fish in your tank can easily form part of the omnivores’ diet.
Because it's fun to see that omnivores appreciate whatever food you give, you could develop a tendency to overfeed them. Remember that a fish's stomach is just about as big as its eye, so introduce just enough food into the tank to fill the tiny stomachs of all the residents. Frequent feedings of small amounts is more appropriate than feeding two large meals a day.
Omnivores need animal flesh as well as vegetables for their health and wellness, so be sure to provide a balanced assortment of foods. Give them fresh greens every so often because they will pick on your aquarium plants if they don’t get their veggies in their regular meals. Likewise, without regular servings of live foods like worms and larvae (even in frozen form), omnivores could develop serious nutritional deficiencies.
For omnivores, the recommended foods are a combination of the herbivore and omnivore diets.
Whether your fishes are plant-eaters, animal-eaters, or plant-and-animal-eaters, always remember these feeding fundamentals:
- Feed only the amount of food that the fish can consume in three to five minutes.
- Provide appropriate quantities of food for the different types of fishes, namely the surface feeders, mid-water feeders, and bottom feeders, including the nocturnal fish.
- Scoop out, or suction off, all uneaten food because it will rot, clog the filters, pollute the water, and render your whole setup toxic.
Always research beforehand your fish’s specific feeding needs, especially the type and size of food they prefer. The success of your community tank depends largely on how you meet your fish’s nutritional requirements.
See also: Feeding Basics and Fish Food Options and Feeding Tips