Could be lymphocytosis. Can you get a side pic? If so needs to be monitored and will go away on it’s own. Should qt the fish so not to spread to other fish. Monitor for any changes in the spot and fish behavior.
Keep it water clean.
Reduce stress and what rocksor has mentioned. Best of luck.Thank you for the reply! I looked up lymphocytosis online and it does sound like that, I got him through the post so he was really stressed out for a few days.. he still is abit jumpy. I am keeping ontop of the water quality and keeping an eye on the white spot also.. so do I just need to keep his stress levels down as much as possible? Keeping the light off etc? Will it eventually drop off? And here is the other picture.
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Thanks for the advice! It ended up falling off a few days after I writ this post BUT I have another problem.. he’s not a very big eater.. when I feel my fish he will eat it then spit most of it back out then he won’t be interested. He’s in there with a female (separated) so I don’t know if that has anything to do with it. He’s very active and always swimming next to the divider to get her attention. He also has white poo.. I don’t know wether that’s because he isn’t eating very well or?? The female is very healthy, she would eat all day if she could?"If" it is Lymphocystis, that is a virus which is ubiquitous, and is like the common cold in humans.
It can't be treated with normal meds, and must run its course, and be beaten by the fishes own immune system.
Lots of water changes, fed properly (not overfed, or under) and a low stress environment are all one can really do.