Recently, I've added a Perlmut and hap. obliquiden and they have died. Now all my other fish are functioning as normal and I dont know why my fish are rolling away. My water levels are great my nitrates are the only thing that are borderline at about 40. I dont know why they just keep dying...both the same way...first very active enjoying themselves then 3-4 days pass and you see heavy breathing. Then next day dead...Of course because i know my water levels are ok i can take them back but the time and gas it cost to get there is becoming to much..Help!!!!