Overfeeding Your Fish
Overfeeding leads to overeating and excess waste, and a habit of overfeeding can lead to water quality issues that can make fish sick. Aim for feeding your fish the amount of food that it will consume in about three minutes. If you notice that too much food winds up trapped in the gravel, reduce the amount you are feeding. If you use flake food, refrain from tipping the bottle over the fish tank, instead take a small pinch with your fingers, or transfer food to an old spice bottle with holes in the top for easier dispensing. If you do overfeed, remove the excess food in the tank with a net.
Most fish are opportunistic feeders and search for food all day long. Grazing herbivorous and young fish (like guppies or small angelfish) may need two small feedings per day and may benefit from having plants to nibble. Some fish are omnivorous and require more protein, like African Cichlids or, in saltwater aquariums, triggerfish. These fish can eat once per day and enjoy a more substantial meal of freeze dried or frozen worms or shrimp. Include scavengers like snails and crabs in your tank to balance out the community and clean up uneaten food.