Why has our oranda turned colour?

[sue]

We have 4 oranda's in our bio orb tank (approx 30 litre ) for approx 6 months. One of the orange and white oranda's has turned lost most of its deep orange pigmentation but still looks healthy. Why? Are we doing something wrong?

 

[aquariumfishguy]

Goldfish often change colors, it depends on the fish itself and the genetic links. It many cases, it is nothing to be worried about - although some diseased fish will change colors as a first symptom. Just watch this fish closely. What size aquarium/pond is the fish in?

 

[sue]

our fish are ina bio orb which is approx 30 litre tank

 

[phanmc]

That's a very small tank for 4 goldfishes, which produce alot of waste.

 

[aquariumfishguy]

Isn't that like 7 or so gallons? Goldfish should have about 20 gallons each and as a bare minimum.