We lost a Black Neon today I can't say I'm very suprised though. The poor things are covered in white spots, more than any one else and all but 1 of them are very pale in colour.
I think our problem is that we have too many fish in the middle area of our tank (I'm Aimee, Josh is at work). We have 14 (was 15) Tetras all together, 6 Platies, 1 Guppy and 2 BNs, and the 4 babies. All our levels are pretty good, Ammonia and Nitrite at 0 and Nitrate is at 5 (the 22G tank has been at these levels for quite some time, the 10G tank has had Ammonia at 0.10, Nitrite at 0.25 and Nitrate at 7.5, But that's all evend off to 0's and a 5 for Nitrate now.), the only thing that I was worried about last week was a spike in our pH, it went up to 7.6 (it was gradually increasing from week to week), so I got some pH adjust and over a couple of days got the pH down to about 7-7.2. Could the increase of the pH been stressful enough to cause this?
Josh very reluctantly disabled and packed up his marine tank (about 15G), so we can use it to put some of the fish from the big tank in, when they're better and when the tank has cycled. He made me agree that the next tank we buy is a 200-300L Marine tank (that'll be a wee way off yet)!