I've had a 30g grow-out tank for some time now. Only problem before was a batch of albino zebras that just had issues, so they were removed.
I am now watching them die off one by one and fast. They tip to their sides, swim wildly in circles and gasp. They have plenty of air and water flow. Some when dead have mouths gaped wide open. I just don't get it.
Since then things were fine more batches were added. Blaa, Blaa, blaa. Well this weekend I finally got sick of fighting with the sun and moved the tank to the basement storage room. They kept a good amount of their water they always had a glass bottom so rock is not a issue I switched to a HOB
filter. I one problem was heat. The room is not insulated so getting up to temp was slow. We now have it insulated and one meter is reading 77.8 and another 80. I had a oh crap moment and realized I didn't use old filter media from their old sponge filter, but yet what they had was not straight out of a box either.
So is it filter related? Heat? Light? What?