Hi, anyone out there! I have a Cobolt Blue discus (about 100mm dia.) which actually looks perfectly healthy and colourful, but is hovering about the bottom of the tank, and has (what seems) a rather full belly, and is breathing in gasps. All the other discus and fishes are looking great with no apparent problems. My water test results (last night) showed "Good" except for a high PO4 (phosphate) reading of 5, but that only came up after dosing the tank with pH (down), which is currently at 7.4. Can anyone advise me as to what the problem with my poor discus is?