Minnow

Question
Hi, I have had a mixed tank of 1 large goldfish, 1 gudgeon,1 smaller goldfish, 1 sucker fish and 2 pink minnows for about 6 months. Recently one of the minnows became rather fat and we thought maybe it was going to spawn, however it now has red marks on its sides looking a bit like blood blisters. It seems quite happy swimming and eating, but looking awful. All the other fish are fine. Any ideas. The water is half changed every week - 8 gallons at a time. Any ideas?

Answer
Hi Charlie;

I've seen this sort of thing before in danios and nothing I ever tried ever helped. The possible causes are many; There can be fluid buildup in the body cavity from organ failure, tumors, internal infection, etc. Many fish afflicted seem to live very long lives in spite of their appearance. It really depends on the cause. It's impossible to know that though unless we could do diagnostic tests like we do in people and four-legged pets. Wish I could help you more...

At Your Service;
Chris Robbins