(08-27-2012, 10:51 AM)writer811 Wrote: I knew fish could go a short time without eating but going for weeks sounds pretty extreme for such a small creature. When I have fish, I feed them daily but my grandma had fish that she fed every other day. She said that feeding them daily would kill them (I don't think that's true as I've had many fish and feeding them daily never seems to hurt them).
Actually fish use very little energy to stay alive. I think you are thinking on a mammal/bird term. Mammal and birds need to keep body heat, which cost a lot of energy just to stay alive, thus both must eat a lot. Fish is cold blood animal, they don't need to eat that much. Fish's stomach is also as small as their eyes. Overfeeding is one of the top causes for fish deaths.
It is also proven that fish can go for 3 weeks without eating anything at all. Even humans can do that as long as they drink plenty of water. Of course, it is not recommended to try.
I have skipped feeding on a few occasions when there was a problem with water quality. There was no ill effect. However, I really don't see fasting fish bring any benefit when it's done on a regular basis.
Mammal and birds need to keep body heat, which cost a lot of energy just to stay alive, thus both must eat a lot. Fish is cold blood animal, they don't need to eat that much. Fish's stomach is also as small as their eyes. Overfeeding is one of the top causes for fish deaths. 
