Developments this evening - just had another look in the tank and this has either burst or been bitten - it's all pink and raw inside, again it'll be impossible to get a picture of ... I added melafix and pimafix, went searching for iodine but can't find it...

Bit panicky now and not sure what to do!

Well done!

Wish I had your willpower! Well, I'll have to have now since I'm fully stocked.

Picture of Spot! He's massively confused by cameras.

Pleased to report he's swimming about normally, with no leaning to the side. He's not used to sinking food yet, and doesn't really understand what it is. Kinda heartbreaking, but he's getting there. Massive improvement on the very sick fish in the shop.

However he does still have the white circles around his eyes - hoping it's not popeye but rather just a defect.

@Jon - there's the Juwel internal in the 350L, and then I have a Eheim 3e 2074 external, this is for tanks to 350 litres (should have gotten the 2078, but I didn't know enough at the time ) - it turns over 2-3 times the tank capacity an hour apparently.

This will have to do them til we buy a house in the next 12 months or so, and I have room for my 1200L tank. That Mr V doesn't know about yet.

She's a little oranda. She's the smallest in the tank, but she's extremely feisty, and thinks she's the biggest.

I'm a total softy, he's been there for weeks now, and he's just been looking more and more poorly every time I go up, but today was the worst. I'll be keeping him in the quarantine tank until he goes one way or the other, although the main tank isn't too healthy atm either, with my ranchu and his lump and little fishy's floaty problems!

I'm not extremely popular with Mr V right now either, I might need a quarantine room for him too.

Moved Boo into the big tank, after a week of fin nipping and a bit of aggression, he was quickly put in his place by the littlest fish, so it's all peace and harmony in there now.

However, and I'll be in trouble for this.... when I went up to the LFS today the lovely orange ranchu was still there, and was getting bitten badly by some form of orange suckerfish thing, he was listing to one side and clamped fins....

... so I brought him home. He's currently unclamped and is swimming merrily around the 100L quarantine tank.

I know I'm going to be overstocked now probably with 5 fish in a 350L, (assuming he survives) but I couldn't leave him there to die like that :/

Try to keep the nitrates below 40ppm, ideally below 20ppm, high nitrates is a cause of tail-streaking so it will improve greatly if kept low.

Herwoman?

Didn't think of that, though I'd have iodined it had I attempted it.

I'll wait and see how it goes, I can bring him to the vet who treats goldfish ( though she was mean to Ronnie) or I can bring him to the LFS who have an aquatic veterinary contact.

My next fish will be selected from the finest stock, and studied for some time before I take him home, rather than falling for the enthusiasm and pleading eyes in the shop :/

I think he's had it about 5 days now, it's gotten a bit bigger in that time, at the start I was hoping it was just 'one of those things' - he's one of two very faulty chus that were the runts of the litter.

There's no colour at all underneath that I can see, just pure black, so I'm speculating that it's some form of cyst or tumour, (speculating all the way up to carp pox and cancerous tumours too).

He's a thrasher too, so when he's caught it's even harder to get a closer look at anything - I'm used to Ronnie who used to sit still once he figured out you were going to Fix the Thing.

If it gets any larger, do you think lancing it might be the way forward? Or I might just hang in there and see what happens :/