How can you make your fish grow faster?

in order to make your fish grow faster, you should feed it nutrient rich foods such as baby brine shrimp, black worms, blood worms, white worms, mysis shrimp, etc. some fish like killifish are actually insect eaters and thrive on fruit flies. live foods or foods that were once alive are always better to boost growth than say, flake food and pellets. if your fish is a vegetarian, spiralina flakes or pellets would then be your best bet. *for baby brine shrimp, they are always the most nutritious when they are newly hatched (preferably 24hrs old). this is when they still have their yold sac, especially great if you are raising fry. another important factor is good water quality. performing at least a 10% water change once a week will also help your fish grow and keep them very healthy.