I would add them all at once. What is the length of the tank? 50 sounds like a lot of fish.
It really depends on the species involved, and if you are buying groups, to remove extra males in the future. Which fish are you purchasing?dmowlin said:1.5m (5feet). Are 50 mbunas way too much you think?
I wouldn't do Yellow Labs and red zebras... too much hybridization risk.dmowlin said:thinking about buying the less agressive types, also one that don't grow as much as some do. So, Yellow Labs, Red Zebras, Jalo reefs, and Rustys. Would like some deep blue ones like the Johannis or Demasonis but have been put off them by their behavious.