My opaline gourami has become more and more agressive....there's plenty of hiding spots and cover, a basically stress free environment. Hes very healthy but over the last couple weeks I sometimes see him chasing one of my sterbais. This morning I found one dead, one of my first that was 4 years old. I almost went to the store to give them the gourami today, but I still really want to keep him, just not if it's costing my other fishes lives. So what would be better off going into a ten, an opaline gourami or 5 sterbais? The tank would be super heavily planted with lots of filtration, I'm thinking the corys?