I'm asking for my DF. He had a two or three fry in his pond last year, and as he's a soft touch he thought they may be eaten and it was cold, he brought them in for a few months, just until they were a bit bigger and it was a bit warmer.
However, one of them either doesn't have a gill cover, or it's folded back (so you can see the gills on one side). So the others went back in the pond, and this one's still inside. It's in splendid isolation in a 100l tank at the moment and other than the gill issue seems happy and healthy, but DF quite fancies having his tank back for something else!
So, his two plans are: a) buy a bigger tank for the goldfish b) put it outside in the pond with the others
He's just worried with the gills uncovered it might be more easily injured or infected/parisitised if in the pond. The other thing is, they're quite sociable aren't they? So it might be happier in the pond? I don't think he really fancies bringing another one in and having a goldfish tank inside and DM might draw the line at four tanks, he only got away with this one as it was supposed to be temporary
Does anybody have any experience of this/any other ideas?
Sounds like it could be a deformity- it may cause problems, it may not. Hard to say, but it would leave the delicate part of the gill exposed. If he kept it inside he would be able to keep a closer eye on it but there's no guarantee it would be OK inside either. Tough decision! If it were me I think I would return it to the pond and just monitor it as closely as I could.