High ammonia/nitrite on established tank?
I've had the tank set up for months now, fully planted and such and I did my regular WC yesterday, but today I woke up to 2 of my neons belly up and the rest of my fish near the surface of the water. CO2 was running as normal, actually lower than normal, but I immediately shut it off and made more surface movement with my canister. I tested the water and the ammonia, nitrite and nitrate are off the charts! I didn't even add my ferts yesterday I totally forgot. So I did a 50% WC again this morning and I'm baffled at what could be causing this sudden cycle. Nothing else has changed, all of the fish have been in there for nearly a month, some from the beginning of setting it up, and they've all been fine until today.
I'll post my H20 params in a bit after I re test the water, but I have a flight lesson at noon so that will have to wait.