Is it ok to let a fish live alone in a tank???

It's hard to say whether or not the fish would prefer it alone or with friends in the tank with her. In some ways I would think she'd like it, more room for her to dart around the tank without running into other fish, also she wouldn't have to fight for her food. But on the other hand, she might like having others in there with her to play tag with.

Seems like the lady has already spoken. LOL. Fish eat other fish constantly. So if your friend gets another fish, she shouldn't be supprized if it happens again. the only thing I've found that works is to make sure all the fish are the exact same size and never ever forget to feed them. I think the fish will be fine if it doesn;t get a new mate.

depending on what kind of fish it is, its fine to leave it alone in a tank. However, chances arethat both your friend's fish were male, since females don't usually kill males

My daughter has a fish on its own and it doesn't seem to be a problem for it. If the one fish killed the other it might be that it will do that to another fish so might be better off on its own.

hmmm, lol, good question..i think why not..yes