fish and pressurized co2

[suprakid95]

when having a good amount of fish in my case 16 red bellies in a tank with plants i need to keep the water well aerated for the fish, is there anyway simple answer as to how i can keep it aerated and use co2 injection together without losing too much co2?

this is for a 125g tank if that helps any running with a canister filter.

 

[jcardona1]

during photosynthesis plants are giving off oxygen, which should be enough for fish. the problem comes at night when the lights go out, since plants take in oxygen. many folks run an airpump on a timer over night, which then turns off when the lights/co2 comes on in the morning.