Red marks on Goldfish

[Zooman]

I have a 30 gallon tank with about 20 gold fish. 2 are fancy and the rest vary in sizes. I noticed today that some of the fish are getting red marks where there front fins attach to there bodys. A couple of the fish have red marks at there tail fins, top fin and under neath there mouth.
Does anyone have any idea what it could be?
Thanks for the help
Matt Jones

[AquariumPro]

Hi Matt:

Those red marks are being caused by blood being shunted to the fins in an effort to pick up oxygen. It would not surprise me if your fish were also gasping at the surface of the tank for air.

MATT! You have way too many fish in that tank! The rule for goldfish is not the same for tropical fish, goldfish need a lot more room, so one inch per gallon won't work! The rule we sue for goldfish is one fish per five gallons of water. You should have six to eight fish in that tank, and your problem will not go away until you get some of them outta there, or buy a 100 gallon aquarium!

In the mean time, start doing small daily water changes of about 10%. That is a bandaid, not a solution. The only solution that is permanent is to remove about half of those fish. :(

[jcnace]

Could this also have been caused by the disease dropsy? I have an oranda that is going through the same thing now. It is just him and another fancy gf in a 10g, and I just did a 50% waterchange 2 days ago, and started adding antifungal medication. Any advice?

[AquariumPro]

Hi Matt:

No, that is not a symptom of Dropsy, it is a symptom of either low oxygen in the aquarium or an internal bacterial infection. I need more information on the 10 gallon tank to help you.

How is the other aquarium doing? Your results with that tank may provide some clues.