yesterday I recieved a bunch of stem plants, and floated them all at the top for a while. I took out 1/3 of my substrate and replaced it with fluorite from another tank that I was taking down. I did 40% water change yesterday to get rid of the cloudiness from the fluorite. I left the plants floating all night with the filter off so it wouldnt keep stirring up the cloudiness, I was waiting for it to settle.
I woke up this morning and found my black ghost knife dead on the ground. I looked around and found 2 buenos ares tetras dead too. the other was at the top gasping for air. and still is. my striped rapheal catfish is out of hiding and at the top gasping for air, the only ones not affected are my gouraims, that naturally breathe air, and the amount of air in the water doesnt affect them. my african knife fish seems alight, but he can breathe air too if he wants to. my african butterfly fish is fine because he also can breathe air.
so what happened? I didnt disinfect the plants, just rinsed them off. they could have carried something nasty over to my tank. this is a stretch, but I did add the plants at night, so they were using the dark reaction, and used air instead of co2, maybe that took all of the oxygen in the water? turning off the filter didnt cause it since Ive done that before, but it didnt help. the substrate was in a tank that didnt have any fish in it for a week. maybe the helpful bacteria died? that'd also remove allot of oxygen.
looking at the dead fish, all I see wrong is loss of color, and frayed fins. no bloating, their eyes arent even glossed over yet. Ive removed the plants and turned on the filter, dont know what else to do. any help appreciated.
