Carbohydrates

Carbohydrates make up 20-30% of the common commercial foods. While they are
alternate sources of energy, they are not very necessary for fish growth. Though most fish
will handle some amount of carbohydrates, they develop signs of ill health if there is a
high concentration of carbs in their diet. For instance, if young fish ingest too much of
carbs, other nutrients will not be absorbed appropriately by their bodies. That is why
cereal grains, which have very high levels of raw starch, are not ingested fully by fish.