flashing can also have to do with minerals or other things in the water that irritate the fish's skin.
any idea offhand of what to test for exactly?
flashing can also have to do with minerals or other things in the water that irritate the fish's skin.
Ok, using same water in both tanks, one tank is fine, so its probably not the water itself. My thought is that something in your tank is releasing something harmful. are you using any carbon? If so, how often are you changing it, and are you pre soaking it?
Did you do any sterlization or disinfection of the ornaments added? what type of clay pot, and was it used for ANYTHING before it went in the tank?