torn fins ?

[brooklyn483]

my new fish has her fins plitting on her tail and the top fin. does anyone know what could be causing this? i'm thinking its either my other (bigger) fish...which i havent seen him pick on her, or its the rocks in the tank, maybe she's rubbing up against them. could stress cause it? will it heel back to normal? i'm just worried about her, i dont want her to be sick or anything. thanks in advance for the replies
here is a link to some pics of her...
http://s28.photobucket.com/albums/c2...&current=5.jpg

thanks!

[xiaohuang7]

my guess would be those sea rocks in there. coral, even dead, is really sharp. and it's natural for the koi to try and hide...

john

[MikeM]

Yep. The rocks may be attractive, but they are the wrong sort to have around koi. If you are going to keep rocks in an aquarium with small koi, use smooth river rock. (Many will recommend no rock whatsoever. In a pond, I agree. In an all glass aquarium, I think a rock or two can help the koi feel more comfortable if large enough to be able to hide a bit. Be careful that debris does not build up under the rock.)

If the water is top quality, the fins will heal without a problem. Good aeration and water temps in the low 70sF make for a healthy fish. If there is excess food or mulm, bacterial populations will be high and water quality lower than desired...infection may set in.

Enjoy your little one. Soon it will be time for a pond.

[brooklyn483]

thanks, i'll remove the coral today, the other rocks arent jagged and she likes a certain spot underneath one of them. the tank is clean, it just had a water change but to avoid a possible infection i'll clean the underneath of the rocks too.
thanks!