...Our 4 goldfish we quite happy in our small pond, but when the cold weather set in and the pond was at risk of freezing we brought he fish indoors and they are very happy in our biorb halo 30 litre tank. they changed colour to gold really quickly, and then one almost overnight developed a black stripe down his back to the tail and had a black ring round its moth and a black tail making it look a very striking looking fish. N again in the space of a few days the stripe has gone and every trace of black on its tail and mouth have vanished. 2 of the other fish started to darken as if going back to black, now they are getting golder again. they are not ill what going on please
Responses (1)
This sounds very strange, but I think it's actually normal, natural for goldfish to change colors like this. The food that you feed your goldfish, the amount of sunlight they get, a poor water quality, or simply genetics can cause this to happen.
I suggest that you get a test kit to check your water quality. Make sure that you're using a suitable aquarium filter and doing enough water changes. Poor quality water can make your goldfish color fade and is also bad for its health.