Add alot of rock and or caves and a few more fish actually to disperse the aggression. I stock my Mbuna setup at 150% of the normal stocking capacity. I multiply my water volume( not tank size) by 1.5 and divide by the average size of the fish. Assuming you rock it up, you'll have around 40 gallons of functional space. 40x1.5=60 divided by 5( average mbuna size) =12. Overfiltering is a must when overstocking and your water change schedule needs to be spot on.
Another thing to consider is its helpful to have the male to female ratio of at least 1 to 3, so you might want to consider having no more than 2 or 3 species in your tank total, but I bet adding alot of decor will help tons. As your crabro grows, it's going to be a problem. Hyper territorial fish. I have a 6" male and wow is he an ass. And if your pleco is a common, you may want to consider another fish. I have an 18" common in my 300 that I will be rehousing in the next year
Best of luck!
