In response to post"So a few days ago my boesemani rainbowfish was swimming all crazy and he would go upside down then swim crooked then get stuck between some wood or on the bottom so i went ahead and got him out. Since then i noticed one of my two australians was losing color and not eating and just last night i noticed he was swimming all crazy to and got stuck on the bottom. I had to take him out. My last and biggest australian rainbow seems to be doing fine. He was kind of starting to be a slight bully towards the other two but i dont think enough to kill them. All other fish are fine as of now. Was is killing my fish? Well i have the SAME problem. Bosenian , Blue and Millenium rainbows die with no reason. All parameters such as nitrate nitrite,amonia ph,phosphate are all normal. I have tried water changes, quarantined these fish but they still die. They dive up and down in the aquarium and upside down. They get pale and dont eat. My tertras are fine and angels and catfish are ok . I have only problems with the rainbows.