Tropical Fish Foods
The foods known as "staple foods" have been specially formulated to meet the general dietary requirements of fish having evolved in tropical freshwater environments. These staple foods contain a blend of vitamins, carbohydrates, fats & proteins that will meet the nutritional needs of most of these fish. It is, however, a good idea to add treat foods to add variety to the diet & research the feeding habits of the particular tropical fish you are keeping to see if they require additional specific food supplementation in addition to the staple diet.
A good example of this would be Molly varieties & fish from the Rift Lakes, very different fish from opposite sides of the World but both of whom benefit from additional plant material in their diet. In this case then their diet should include a vegetable based feed in addition to the staple offering. Some fish are highly coloured & the colour intensity can be maintained & even enhanced by feeding colour enhancing foods & some fish such as the beefier Central American Cichlids need a higher protein content in their diet.