Good question. I'm not sure.... it's amazing to me how quickly the 240g fills up. And even with avoiding larger species that I so desperately want!!! No queen angel.... no emperor angel.... no chrysurus angel....no clarion or passer...
I'm thinking I would like to add a xanthocephalus but I'm worried about how the ephippium will react. BTW if you notice, the ephippium in the video is very skinny. He finished cupramine treatment. IME ephippium butterflies are one of those that stop eating with cupramine. This is my third specimen in 20+ years, and all 3 had the same issue during treatment.
I'd like to add smaller fish. I'm thinking a C. madagaskariensis because I think it'd be neat to have the paucifasciatus and madagaskariensis in the same tank.
I also lost a gardineri butterfly after a long battle of trying to get it to eat.... I liked the look of that fish though, so I may try to find a C. selene to replace it.
And finally, since I have a Chelmon marginalis and muelleri, I'm thinking of trying a rostratus... but only an aussie one, since they are so much better looking.