Hello, I was wondering if someone could help me. My goldfish (I think she is fancy, but am unsure as she was a fairground fish) has a clamped dorsal fin and is going between lying on the bottom of the tank and sucking at the surface. I've had her for about two years now and have not had a problem. There are two fancies in the tank with her, and neither of them seem affected by whatever's happened to her, even one who is rather sensitive to issues with the tank (have had a lot of swim bladder problems with him) She is swimming around okay but is a bit wonky, and her fin perked up when i tried to feed her, but it has since gone down again. The last water change was about 25% about a week ago and they were fine, the only new thing was a water bubbler (which is rather loud and I was worried it would stress the fish so I don't have it on much) There's a small swelling on her side too. The tank is small (30-40L) and I'm trying to get money/parental permission together to upgrade as I know it isn't ideal. What should I do? Should I try and separate her from the other fish?
When I kept goldfish, I often had problems like this, especially with the fancy goldfish – and it got worse as they got older. I kept treating with aquarium salt or, if something got worse, with medication. What I only found out, years later with the advent of the internet, fish forums, wider knowledge about fish welfare, etc, is that actually most of these problems stemmed from not providing the fish with the correct environment. Now, however, there are very useful summaries and guides about this, such as https://www.fishkeeping.co.uk/modules/ ... esheet.php?caresheetID=83 and http://injaf.org/aquarium-fish/the-goldfish-section/ . You’ll see from this, and from http://injaf.org/aquarium-fish/the-go ... t-size-tank-for-goldfish/, that actually even one goldfish requires a much larger tank, let alone 3. For 3 such fish, you’d need a tank at least the size of something like the Fluval Roma 240 litre tank. Without that, water quality is going to be seriously impaired, unfortunately, leading to conditions such as this which will recur repeatedly, new illnesses/conditions develop, with the weakest fish succumbing first, followed by the others.
As a matter of urgency, therefore, I recommend you: • do a 50% water change daily with dechlorinator to address chlorine and chloramine; • buy a liquid-based water quality test kit which measures ammonia, nitrite and nitrates – and, with such a tiny tank, it will need monitoring daily to ensure that ammonia and nitrite stay consistently at 0 and nitrates stay no higher than 20 above tap water levels; • research and buy a larger tank ASAP – if you can’t afford a new tank, check aquarist-classifieds.co.uk or other second-hand sites (ensuring that the tank is sealed/watertight before purchase); • a 145-litre Really Useful Box would be helpful in the interim until you can get the larger tank [NB when you upgrade, you’ll need a filter with larger capacity but do make sure you transfer the existing filter media into the new tank’s filter, to prevent a fish-in cycle occurring]; • the fish don’t need separated as a result of the condition as I think this is purely a water quality issue; however, if you did have a spare tank/container and filter (with 1/3 of the filter media from this tank moved into the new filter), then that might help the bioload slightly.