Food and Feeding Strategy
Several times I have come across threads and queries about how many times to feed your fish and or about suitability of different foods, so I felt I would like to express myself where I can give an answer which would make the reader understand the matter without limiting myself to the question asked.
Knowing your fishes is a great help in understanding their food and feeding requirements. Like man, digestion starts at the mouth and the food is prepared to enter the digestive system by preparation by the jaws but herbivore and predatory fishes not only have different chewing strategies but also different types of gut system for digestion and your food and feeding strategy requires different approaches for them.
The teeth of a herbivorous fish is situated at its throat, pharyngeal teeth, which chomps and prepares the food by physically grinding it into small pieces, rejecting unwanted parts through its gill covers, opercula. This ground food then passes into a gut system which generally has no large storage system like the human stomach, they either have a very small stomach or like the Koi none at all and a very long gut length. Because of this situation herbivorous fish needs several small meals all through the day.
Although they are herbivore, most of such fishes will not pass by an offer of dead or live fleshy food. Nature has taught them never to look a gift horse at its mouth, and their life depends upon making good with whatever is available.
Although they accept fleshy food does not make them well suited to handle such food continuously or exclusively. Their gut system is more suited to food with a higher degree of roughage. Take the habitat of these fishes, there is silt present and on the plants that they eat, but in our super clean aquariums they hardly will be ingesting enough roughage. Feeding these fishes exclusively on high animal food like shrimp/tubifex/ bloodworm/ earthworm etc will not be healthy for them. Herbivores need greater fiber and complex starch content in their food than predatory fishes to keep healthy.
Most of the high quality, highly digestible fish food available in aquarium hobby is well suited to the needs of the predatory fishes. Their digestive system has a large stomach and a short gut system. Giving these fishes a single large meal would mean that they would store it in their stomach and digest it throughout the day. So when you are feeding predatory fish one large or two medium feeds a day is enough.
Having a short gut length means that the predatory fish cannot digest food with a high content of fibers. So the food must be highly digestible and meaty in nature.
The Mixed Community Tank
What food and feeding strategy then must be followed in a community tank containing large herbivores and small predatory fish? Simple one large feed of highly digestible meaty food followed by several small herbivore foods through the day.