I had 8 goldfishes in my tank, medium in size. I transfer from another tank 2 clown loaches and 2 angel fish into the goldfish tank, will it hurt my goldfishes? Cas I need that tank for something else, so I had no choice and to bring them together. But there is sufficient swimming room for them, I also placed a cave ( an ornament ) for the loaches, just to hope they stay in there and not create trouble.