don't worry about that... you don't have one of those.would my river murry cod be killing them over night ?
I have mollys guppies angles
fish are as follows : 2 guppies small ,angel 1 small ,gouramis 1 small , rainbows 6 med , rainbow shark small 1, black neon tetras 2, red eye tetras 6
oh and 3 swordstails and 3 phatys
Not only could it collect particulates and chemicals but also animal droppings and urine could get into the tank.What is the roof made of? Generally speaking, the rain water used for aquariums should NOT be coming off a roof. Collecting it from direct fall is safe, but coming off a roof, it's going to collect particulates at best, and chemicals that you can't test for at worst.
Normally I agree but the nitrogenous waste from just 11 small fish in over 2,000 gallons of water is not going to register on the test kits available to hobbyists. That is A LOT of dilution power.A River Murray Cod is a predator, so it's possible.
To clarify, you said you got all 0s on your ammonia, nitrite, and nitrate tests. Is that correct? If so, something is wrong.
Not necessarily. The nitrate may be reading 0 ppm, but they may actually be so low that they are not able to be registered by the API kit which is only able to go as low as 5 ppm. The OP has a lot of water and a very light stocking right now.additionally, if there are no readings for nitrates (being at 0), the tank is uncycled.