Overfeeding is the number one cause of fish loss, and it’s not hard to see why. It is easy to forget how small our pet fish really are, and the fact that their appetites are not the same as ours. Also, because feeding our fish is the main way we interact with them, they certainly come to expect at least a little sprinkle of food each time we approach their tank—and it’s hard sometimes not to give in. However, hungry as they may seem to be, it is important to remember that overfeeding your fish can have serious consequences.

Contrary to popular belief, most fish who die of overfeeding do not actually suffer from any sort of gastrointestinal problem. In fact, the major issue is unrelated to the actual over-ingestion of food. Rather, problems occur when excess food is left uneaten and accumulates as waste in the aquarium. The products of decomposed fish food can be extremely toxic to fish and can also indirectly affect them by wreaking havoc in their aquarium environment. Common signs of overfeeding are easily observable in any fish tank; cloudy water, algae growth, mold/fungi, and clogged filters are some of the most obvious indicators.