I got two 5" Round Air Stones on each side of the tank and at times the fish move the air disks and the go under the coralinas and they chop up the bubbles to really fine bubbles so I dont think oxygen is the issue. I had the other 2 tigs in a different tank, when thye got big enough I put them in the other tank but didnt last long.
I guess my only option is to do more water changes for now.
All the fish have no marks on them, tigs look like they are alive when dead and so did the Bowfin. They royals didnt even get to them yet.
There is the normal chasing of fish, my NGT is a bully but he doesnt hurt anyone. And when I add new fish in, they dont bother them, I watch them for a while just to make sure nothing happens.