What to do with aggressive fish

so my rainbow shark is picking on my gold gourami i dont know why they have been together for over a month and this is the first time this has happended i dont have any other tank to seprate him i only have the breeding separater thing but thats the sizes of the rainbow shark so im not sure hell fit what should i do?

Well, you posted this in the wrong category for starters. As for the shark. Thats what they do, they are aggressive. They will chase and harass. GOOGLE the fish and read up on it, then make your decision.

Of course a larger tank does help. The 37g you have has the same foot print as the 29g just taller? Great show tank but not always the best for real life fish keeping. A 48" tank like the standard 55g would probably help but like madness said: "Thats what they do, they are aggressive. They will chase and harass." Thats just the nature of the fish. Better suited to keep with cichlids than gourami.

I always overcrowd the tank.... Ive tried several things... a timeout tank... seperating them.... putting in a bigger fish..... but what always does the trick was to overcrowd the tank....

So Jose, if you overcrowd, be sure to over-filter too. Let me know if that's what you choose to do. I'll help you with HOB filters. Hi to the family....

Ron

Just to balance the conversation... Not all fish do well with overcrowding. I don't know Gourami very well and can't speak to them specifically.

The rainbow started to act like this right when i put in the female pearl gourami every time the gold gourami(male) gets close to her the shark goes after him