Gold Fish

[TopCat1]

I bought my daughter 2 goldfish about a month ago, and one of them died yesterday. Part of its tail was missing. The day before this, I noticed that its tail/back was flopping down (almost like it was broke). Anyone any ideas how this happened?

Just asking incase its a disease, which the other one might have, as I don't want to go and replace the fish, if its gonna get sick too.

[covert]

It sounds to me like one of your fish bullied the other. The part of the tail missing was probably bitten off by the other fish.

this may or may not be true depending on:

The size of the fish tank

How often you clean it- the "flopping down" you mentioned happens to my fish if i do not clean thier tank often.

Do you de-chlorinate the water? Chloring has horrible effects.

It is not likely to be a disease unless there are other symptoms.

This may not be the case, but many people buy golfish thinking you can stick them in a glass of water and they will live happily, when in fact they are not so easy to look after.

[amaham]

As covert says, it does sound a lot like bullying. But also the water content does need looking at as well because it can get poisoned from overfeeding. Do you you have plants and an oxygenator pump in the tank?