I transferred the fish from my old tank to a new one that is bigger. After a few days fish started acting abnormally - go to the bottom or stay at the top grasping for air (the tank has good air flow). I checked the pH and ammonia levels right away, and they are fine. They are dying one after another with no symptoms of illness, which must mean it is because of the water quality. Before I put the fish in the new tank, I left the tank for a couple of days to stabilize and added all the necessary water treatment chemicals. I also used for the first time some planth growth enhancer because I planted live plants. It says it adds iron to the water. Can an increased level of iron cause harm to the fish? I don't know what to do? Is it because the tank needs more time for it to become biologically stable and how can I prevent further death of fish?
Help appreciated!
Help appreciated!