Reptile & Amphibian Forums

Over the last few days one of my goldfish developed black patches on its body. It is the size and shape of a young male. I say this because there has been a fair amount of spawning activity lately - chasing, burrowing in the moss etc. It acts normally and is eating fine. I have not been able to net it to inspect it closely or take a pic. Now a couple other fish have developed the same thing. I have a 5000 pond and the checked water quality is fine except the pH is a bit high (8.5). Should I be worried?

Thanks for any help.
Gary

Hi
as goldfish dont turn black then i suspect what you are seeing could be melanophore migration. The pigment in the skin darkens in reaction to ammonia/nitrite burning and is because at some stage you had a spike of one or the other or both. maybe a mini cycle. The blackening is the skin healing and if it is the culprit then they should start to get healthy again in a few weeks. Keep testing the water for ammonia and nitrites. If your test kit is more than 6 months old then you should get new ones. Hope that helped.

Thanks for the reply. My kit is about 18 months old so I will take your advice and get a new one. Nitrates and ammonia have always tested at the lowest reading and I do not have a very great fish load, 40 goldfish and 5 small koi in 7,500 gallons of pond, stream, several falls, biological filters etc.

Thanks for the advice.

Gary