What’s wrong with my goldfish?
I wonder if you can diagnose the problem with this goldfish? At first it had the appearance of carp pox and I expected it to go in due course but it has persisted for about 18 months. Recently there have been some reddened eruptions. The fish feeds well and does not exhibit any symptoms of stress. ALEX LEVACK, BY EMAIL
DR PETER BURGESS SAYS:
From your photos, and due to the slow development of this condition, I’m pretty sure your goldfish has some sort of benign tumour disease.
Skin tumours, such as fibromas, are not uncommon in goldfish, though most cases that I have seen were limited to just one or a few lumpy masses, whereas your poor fish has many lumps!
Goldfish (and other types of fish) can also develop pigment cell tumours. These include melanomas (black tumours associated with the black pigment cells of the skin) and erythrophoromas (red pigment cell tumours). You mention the lumps appear reddish, so an erythrophoroma could possibly be the cause.
Unfortunately, it’s almost impossible to identify the type or seriousness of a tumour based on visual appearances: instead it would be necessary to remove a piece of tumour and subject it to special laboratory tests and microscopy (which would be expensive and won’t lead to a cure).
Tumours can arise spontaneously, and do not indicate poor nutrition, bad husbandry or any other fault on the part of the fishkeeper. These tumours are not infectious so will not spread to other fish sharing the aquarium.
Some of these skin tumours are not particularly harmful, unless they inhibit vital areas, such as the gills, mouth or vent. Some tumours, however, are lethal. None of them are curable, though, so chemical or other remedies simply won’t work.
While your fish remains otherwise healthy, swims normally and has a good appetite then do nothing. If it starts to fail, though, you will have to consider euthanasia.
Fingers crossed that your fish will remain okay for many more months!
The lumps on Alex’s goldfish haven’t bothered it so far.