poorly fish

Question
i have three goldfish in a 60ltr biorb,two are gold  coloured[sushi and scampi] and one is a grey/blue colour[shrimp]yesturday i noticed that shrimp is lying on the bottom of the tank. although from time to time he does try and swim, he is still breathing[just] but is looking very dark in colour with a reddy brown tint and is slightly bloated.we have had shrimp about 6 months. we had another fish a black one with bobbly eyes[ainsley] and he died, also a funny colour. I had the water tested and it was fine. The other two seem really happy.Can you help before it is too late.
Many thanks
Karen

Answer
Your tank is really overstocked.

You could barely fit one goldfish in there never mind three or four!  Sorry to be harsh.

I think you should restock as it iss cruel to keep them all in there.  I would take them back and get 5-8 zebra/leopard/pearl danios as they are fast and movement to the tank.

Sorry to be harsh :)

Good Luck     Jack