We all know how difficult it is to identify the sex of these fish, so please post a picture in here and we'll try to help you (or at least give an educated guess!).
Because of the spots on the tail, I have named this one freckles.
He/she quite likes living in caves so I am not quite sure of the sex.
I took as many photos as possible to help.
Glad you brought it up addict, as I had noticed a strangeness toward the tail but not really paid much attention.
Here is a photo which the previous owner took way back in August this year and the tail looks like there is a cyst like swelling on one side of the tail there as well.
Not much I can really do about it but hope it never gets any worse.
She doesn't seem to be slowed down or sick or anything by it.
to me looks as thought the tail or spine could have been damaged or broken when young and has healed causing the disfiggurement rather than a cyst. also looks to be a female.