Feeding fish – What to feed, how much, how often
Feeding fish is simple isn’t it? You just sprinkle a few flakes of fish food into the tank daily and that’s all they need. Well no, there’s more to it than that. While some small tropical fish will survive on a simple manufactured flake diet, others have specialised dietary needs and if you give a little consideration to their diet, most will be more active, more colourful, healthier and live longer lives.
What do aquarium fish eat?
Fish have evolved to use foods in their environment; consequently certain foods are appropriate for their digestive systems. Some fish have a very long digestive tract because extracting nutrients from plant sources or algae and the microscopic lifeforms that live in it (aufwuchs) takes more time. The digestive tract of fish adapted to a carnivorous diet is the opposite: insects, invertebrates, other fish and so on are digested differently. Many fish are omnivores which means they can use both vegetable and animal based foods. These species’ will usually favour one more than the other. Furthermore, feeding carnivores a largely plant based diet or herbivores animal protein can cause problems because their digestion is not designed for those foods.
Clues to diet
You can usually hazard a guess at what foods a fish will need simply by looking at the shape of its mouth. Mouths turn upwards in fish that primarily feed from the surface of the water and are downward facing in those the dig around for food on the bottom.
The Zebra Danio (Danio rerio) feeds from the water surface and his upturned mouth is clearly designed to do just that. Another surface feeding fish, familiar to most,is the Siamese Fighting Fish (Betta splendens). This image shows the upturned mouth clearly.
On the other hand, there are many fish whose mouths turn down rather than up. That’s because their preferred food source is found on the bed of the waters they come from. Gold Laser Cory (Corydoras CW010), is a typical example of a bottom-feeding fish . In addition to the down turned mouth, the Cory also has whiskery barbels projecting from the sides of his face. He uses these sensitive feelers to locate food buried in the mud or sand.
Many fish hunt for food in mid water areas. Their niche suits a forward facing mouth best: the Rotkeil Severum (Heros Sp.”Rotkeil”) below is an example of a fish with a forward facing mouth.
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