Learning the ropes of aggressive and predatory fish

[IFLAquatics]

So I'm starting to notice patterns. Whenever I put larger and equally aggressive fish with each other they tend to find specific roles. I have a terrible idea going right now, temporarily, of course due to security issues with my larger more aggressive Dovii male.
Well I have two Dovii I have been trying to split house together and it wasn't working out because he would jump the wall and terrorize her. He has never hurt her but I know he will if he gets over there for too long. So we decided to place the female in the 75 with a large convict cichlid at least 5 times her weight and 3 times her length, a green terror her size, a Senegal bichir 10 " And a leopard lace catfish that's almost 8 inche and assorted cats.
What I'm getting at is that the convict cichlid almost acts like the bouncer of the tank. The terror flares at her and the convict swims in between them and basically parents them . Does anyone know any reasoning behind this? I don't get it, the Dovii should be murdering the terror and vice versa and

 

[Steve132]

I honestly have no idea why this happens but my pacu does the same thing. I have a 14” tiger Oscar / 8” JD / 8” jag that get a little sporty during feeding time. As soon as mouths open the albino pacu swoops in and kind of pushed everyone away. Crazy to watch but I know what you mean

 

[krichardson]

I had an Oreochromis Tanganyikae that would act as the boss and regulator of the tank.It would keep to itself until other fish would squabble,then it would spring into action and chase the others around for a few minutes.I don't have many issues between the group of fish that I currently have but I sure miss that big ol fish.