Originally Posted by Perry the platypus
1 goldfish is 4 inches long and 2 inches in width. The other one is 3 in. long and 1 in. in width. 2 of them are also 3 in. long but 1 in. width. The smallest one is 2 in. long and 1/2 in. width.
In general, the rule for goldfish is at least 20 gallons for the first one and ten gallons for each additional fish as long as the tank has DOUBLE the filtration for its size.
For example, at my workplace there is a 29 gallon tank with 3 goldfish in it. It has 2 GIANT filters on it, more double the capacity of the tank. It has filtration for 75 gallons.
BC goldfish produce more ammonia than other fish. They need additional oxygen, too, so airstones are recommended (the filters at work are HOB, so lots of surface agitation, no airstone necessary).
Please re-home your fish. They are slowly dying a painful death by ammonia burn to the gills.