What water suits your species?
Every fish, shrimp and crayfish has a comfort zone for temperature, pH and the waste chemicals your filter has to keep down. Pick a species to see sensible target ranges to aim for at home, along with a one-line note on what tends to trip people up. Ammonia and nitrite should always sit at or near zero.
Target ranges Tilapia warm-water, very tough
Temperature:
pH:
Ammonia (NH3):
Nitrite (NO2):
Nitrate (NO3):
⚠️ Starting guides, not lab specs. Published tolerances vary between sources and strains, and your fish will adapt to steady, slightly-off conditions better than to sudden swings. Aim for stability first, then the middle of these ranges. A test kit and your own records beat any table.