Lupin - I honestly wouldn't want to have a go at it myself. I will honestly start panicking and end up doing something wrong. I would much rather have a real vet do it. I live in Essex in England. I do my best to keep the water clean and fresh(you know what I mean). I feed them enough, not too much, but enough for them. So, I'm hoping he will live well and long. They are both about 7years old, so I don't know how long they have left. I will ring up my local vet on Monday and see it they deal with fish, I'm hoping they will say yes, and then take him down so they can have a look and let me know what they think.
Cerianthus - It may very well be causing some discomfort, but it just doesn't look as though it is. It swims fine and eats well.