We have a 55l fish tank which is the home of a goldfish, lemon goldfish and a sarasa. We've had them about a month.
We have recently noticed that the sarasa has been floating around close to the surface and almost looks as if it is struggling to swim and gulping for air. The other two fish seem fine. This morning it seemed a bit perkier, but not the same as it was when we first got it.
We recently tested the water, changed it and cleaned the gravel etc.
DH seems to think that as it is not a goldfish, it may be being ostracised by the others. We have seen that he is more on his own lately, whereas when we got them, they would all be swimming around together.
To make things worse, DH has been reading up and discovered that apparently it is not advisable to put goldfish with other, more delicate, fish (we were not advised of this when we bought them). So now I am feeling guilty for putting it in . He also thinks there may be some slight fin damage.
I am at work at the moment, so can't give any running commentary on how it's behaving, but any advice based on what I have typed would be great .
A sarasa is a goldfish Goldfish are like dogs; one species but lots of different breeds. There is nothing wrong with the combination of fish you have, the only real differences between types of common-shape goldfish are superficial things like colour and finnage (fancy goldfish are a different ballgame).
The aggression you are seeing could be because you are overstocked. Sadly your tank isn't big enough for one goldfish, let alone three. You were probably told by the shop that it was OK, but most pet shops are crap and just don't know how big goldfish get.
The fish you have are bred to be pond fish, so they are active and they grow quite large. Around 10 inches is normal for this sort of fish. In a small tank they will become stunted which can cause all sorts of health problems. Also they will produce too much waste for the system to cope with.
Unfortunately the only long term option is to get them a large enough tank (you will want to be sitting down with a stiff drink when you read this ) or find a suitable pond. If you do need to rehome them then you could try local aquatic or gardening groups on Facebook, or try your local council to see if there's a fish pond they can go in.
The silver lining is that there are lots of fish that can live happily in a 55 litre tank but sorry for all the rest of the doom and gloom.
Neons are tropical, yes. But there's no reason that tropical is more complicated than coldwater. The hard part is the choice of fish because there are many more tropical species available, but if you choose carefully then the rest is just as easy as coldwater. You could add a heater to your 55 litre and have some neons in there.