Carbon dioxide level >60 ppm
Normal CO2 level is exceeded.
CO2 level too high, Carbonates and Bicarbonates too low.
Check levels of CO2 and Carbonate levels with test kits. Problem can be remedied easily if cause is determined within a few hours.
The level of CO2 in both fish farms and aquaria can easily be kept to safe levels by use of a CO2 controller.