So most of your fish are under a year old, as these fish can live upto 15 years except the flowerhorn I think your a bit premature, if there all living together in 5 years I will quite happily doth my cap to you
Sexual maturity can be like a light switch when it comes to personality/aggression. The GT may become nasty, maybe not. A salvini will likely try to attack everything in sight.Right now the Oscar is the boss of the tank and nobody messes with him, the other cichlids have minimal aggression twords each other occasional flaring and chasing. I was thinking a salvini would work beacause even though there aggressive there size would keep them in check I did some research on the argentea and knocked that off my list after I saw all the people saying they were very aggressive.
Sexual maturity can be like a light switch when it comes to personality/aggression. The GT may become nasty, maybe not. A salvini will likely try to attack everything in sight.
Think there's alot of difference in salvini personality, my old 6/7 inch male was a aggressive pita in my 180 galIn 180g a salvini will not attack everything lol. I've never had any aggression issues in my 150g. IMO salvinis have gained a bad reputation because many people keep them in 30-50g tanks. Only breeding pairs really get nasty.
In my experience, if you are going to understock a CA/SA tank then it must be really understocked with non aggressive fishes. I have had better results with overstocking with agreessive cichlids.
To be honest you will have nipped fins here and there regardless on how you stock it.
In that case I think I'm going to get one or two mid sized/small cichids and some dithers and if there's an issue I can always give a problem fish to my LFS.