Last xmas i bought a small tank for my daughter and got 1 common goldfish and 1 black moor.
they have been fine together for the past 9 months or so but this past month the goldfish is constantly charging at the black moor. the black moor has even started to rest of the stones at the bottom a lot more now.
what is going on?
Common goldfish can reach a length of 8 inches or more in a large aquarium and well over 12 inches in a large pond. So you can see they require a lot of space. Generally you need about 30 gallon aquarium for the two goldfish. If the tank is anything smaller, they will bully each other because of overcrowding. My guess is that they have outgrown their current tank.