in a 75G the typical advice is about 4 breeds 1M:5F. What if one of those breeds is demasoni? So in my 75 i put in 18 demasoni assuming that number will dwindle down after they establish hierarchy. Since they are dwarf, can i do 3 other breeds at 1m:5F?
With demasoni since they are difficult and fishkeepers have better luck with large groups, I would not have 4 species.
In a 75G 15 individuals after removing extra males would be ideal. Then another one or two species with 1m:4f could work...avoid blue barred species.
Keeping the numbers high manages aggression for most people better than 1m:4f with demasoni. I tried 9 once and then I learned about bloat. Since then I kept 20 in the 72" tank and now I always have at least 15 in the 48x18" tank.
FYI they shouldn't dwindle down...you would rehome any fish that are rejected while they are still healthy and can be rehomed. Letting them kill each other off can lead to disease.