Carnivores , such as Needle fish, Jack Dempseys, and Bettas, are meat eaters. These predatory fish may only eat meaty foods such as brine shrimp, freeze-dried tubifex worms, bloodworms, and small feeder fish. Herbivores , such as Plecos, African Cichlids, Pacus, and Silver Dollars, are plant eaters. They do well with staple flake foods and algae wafers. They can also be supplemented with finely chopped lettuce, spinach, zucchini, or green peas.
Omnivores are both plant and meat eaters.
Good examples of omnivorous fish would be mollies, catfish, crayfish, and goldfish. Their diet should consist of a staple flake food. Goldfish will benefit from specially formulated Goldfish flakes and pelleted foods. Fish foods are designed around the way fish eat, which is why you should know about the shape and placement of the fish's mouth. They like to feed off the surface.