One of my guppies is in a bad way. His tail is totally clamped and looks stuck like that. He hadn't been too active for a few days and I had wondered if he was OK. And last night I noticed he was trying to eat, chasing food, but didn't seem able to eat. Also, he seemed a bit slow and unstable so i popped him into a breeding net away from the other guppies, who are all fine. Today he keeps lying on the bottom of the net, and only moves when I move the net to see if he is dead. I have dosed the tank with anti internal bacteria meds. The water stats are all fine, no change to what they have been for months - 0 ammo, 0 nitrite, ph around 7. No changes made to tank decor. Nothing gets sprayed in the room that could affect the tank, and besides, the other fish are fine. Any ideas what might be wrong? He does seem to be lying slightly on his side, and he has never been a fat fish but I am sure he is skinnier than usual....

Too late. poor lil thing died. At least he didn't get nibbled by the other guppies.

Sorry about him dieing.

When guppies get clamped fins it is usually caused by a bacterial infection. Regular water changes and gravel cleans are a must to prevent these from occurring. Adding salt to the water can help reduce problems like this but if you have Corydoras catfish or discus in the tank avoid salt. You can increase the general hardness (GH) and this will often help reduce problems in livebearers like guppies.

Thanks Colin. All my other guppies are still fine, and I do a weekly 25% water change with gravel clean so I guess I just got unlucky with this one I'll add some salt though as there are only guppies in the tank at present.