My fish doesn't look very happy at all.

[GallumDrawnAndQuartered]

only had it about 10 days.

it's tail looks tatty and it's sort of hovvering by twitching it's tail quickly.

the other 2 look fine.

any ideas?

[Ryoko]

Could be bullying have you been watching them, to make sure the other two haven't been harassing it and nibbling it's tail?.

[EauRouge]

Did you cycle the tank before you put fish in? Take a look at this- new tank syndrome. A fishless cycle takes around 6 weeks. The other 2 might look alright now, it's always the weakest fish that shows signs of illness first.

For now I would do a large-ish (about 50%) water change to be on the safe side. You'll need a water testing kit to check on the water quality- make sure you get a decent quality liquid kit, the dipstick ones are massively inaccurate.

[GallumDrawnAndQuartered]

does that come over them quickly? could be. should i take it out of the tank? i can get some medicine in the morning. will that be too late?

[LynetteScavo]

fin rot?

[GallumDrawnAndQuartered]

and it looked fine this morning.