Confused

[shelby07]

hello, about 5 days go, i bought 2 orange mollies, perfectly fine, 2 days ago on one of the fish i noticed it wasnt using one of his fins??? he keeps going to the bottom of the tank and now the fin has gone very red and it is fluffy (it sorta looks moldy)

can you tell me what it is and what i should do???

thank you

shels
xx

 

[Hollymolly4]

Fin rot? I don't know for sure. I'm sure someone will know.

 

[big-george91]

could u post a pic for a better identification of the problem