A Lake Malawi mbuna. Males are blue, females yellow. More aggressive than the yellow lab, so keep several together to spread the aggression. Lake Malawi water has higher alkalinity than hardness, so raising pH and KH matters more than GH — coral sand and calcareous stone do that job.
The largest group where none died in 90 days. Tap water · coral sand · bacteria starter on day 1 · fish added on day 10 · 25% weekly water changes.
It likes hard water (high pH and hardness). This was calculated with coral sand to harden the water.
Run a 120 cm standard tank with 6 yourself →The same rules the engine uses for tankmates.
No eating or bullying either way, with plenty of overlap in temperature and pH. Fish that swim at a different level come first.
The numbers on this page come from the Water Kiwoogi simulator model; real tanks can differ.