300 litre/80 gallon aquarium stocking

[TriangulumDelta]

I have a 300 litre/80 gallon aquarium with four fancy goldfish (three fantail goldfish and a black moor). How many more fancy goldfish can I put in the aquarium or have I hit the limit?

 

[tzabor10]

Most of us are reef keepers here. But goldfish seem cool. Add them until your parameters get worse, or they start fighting.