TNG
Fishaholic
Just wondering what the problem is with these 2 fish? Currently in isolation tank, they’re around 2 years old, have been swimming like that for the past 3 weeks or so, still eating but not as much as they did.
I'm actually also curious about this issue, because I've noticed one of my new neons swimming somewhat similarly to this the past couple days, with the back half sinking slightly when the fish is motionless. I'm pretty sure I only noticed it after the affected fish ate too much and got a bit bloated, so I'm fasting and might feed peas, and I can't see any other obvious symptoms of a wasting disease, but it would be good to know whether this is likely a deeper problem. I'll be interested to hear Colin's response if he sees this.You may never get an answer, as so many things can cause that behaviour. The isolation tank is an excellent idea though.
It's presenting as an internal wasting disease. It's what you'd expect with old age (but the fish aren't old). On the outside chance it's Mycobacter (2 sick fish may have been carrying it since you got them from the same batch) I'd maintain QT or euthanize. But I live in a jurisdiction with few medication resources.
@Colin_T may be able to help, and is in Australia.