I have 4 shubunkins who have been fit and well for 5 months now in an aquarium. One of the fish started to behave strangely about 3 weeks ago and spent periods sitting on the gravel at the bottom of the aquarium being inactive. There are no external signs of disease although balance appeared to be affected. These symptoms appear to have disappeared over the last week or so. The fish now has a large area removed from one of it's fins - it looks more like an attack from another fish rather than finrot to me.
Any ideas of what I should do - or is it just a case of waiting and seeing? Do fins tend to recover from damage?