[DJRansome]

Pheno's are timid so you may be better off with a colony rather than all male.

I like 18 males in all male for a 72" tank.

For mixed gender (remember the pheno's get large) maybe 3m:9f of the phenos and 1m:4f of yellow labs?

The problem with stocking juveniles for all-male is that you can't know when a fish is male until it is no longer a juvenile.

 

[DJRansome]

I would say no to giant demasoni and maybe to yellow labs. Phenos are a hap that are intimidated even by many other haps.