A tiny orange crayfish. Small and fairly calm, so it can live with fish, but it eats small shrimp and snails. Rocks or driftwood help it hide while molting. Copper medication wipes it out.
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 60 cm standard tank with 21 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.