Many bony fish species are semi-selective eaters, eating some foods more than others. B. Food intake. The amount of food a bony fish eats is directly related to its size, its metabolic rate, and the temperature of its environment. Smaller fishes generally have a higher metabolic rate than large fishes of the same species. Thus, small fishes generally eat more relative to their body size.
Some bony fishes can go long periods without eating.
Some researchers have calculated food intake. C. Methods of collecting and eating food. Predatory fishes prey most often on weak members of an animal population. They select weak, ill, injured, or dying prey because it is easier to catch. They strain plankton from the water with gill rakers.