If you are considering getting another goldie, you should make it another moor or a telescope. Moors are visually handicapped and if you put a regular goldie in with him, the regular goldie will find all the food first and you will end up overfeeding the fish just to make sure the moor gets to eat at all. another fish with similar vision will make it easier.
Consider getting a bigger tank as well. It doesn't see like a problem when they are very small but as they grow they will quickly overwhelm your filter, and your water quality will start to suffer and then so will the fish.
You should have a minimum of 20 gal for 2 goldies....for now. They get big!
|