Anybody know why some neons/cardinals

[luxum]

I've always wondered this. In pictures i almost always see neons and cardinals with a true blue stripe. About 3/4 of mine are like this, but a few of them have a blue stripe that is more turquoise, greenish, than the others. Over the years i've seen this many times, and it seems that it may be a water condition issue since some fish with the true blue stripe will end up with a turquoise stripe instead after a while. Does anyone know why? Is this just some recessive genetic characteristic and i'm imagining that some fish seem to develop it after a while, maybe i just never noticed? Or is it related to Ph perhaps? My tank is currently 0 amm, 0 nitrI, 10 or lower ppm nitrA, and a Ph of 7.0 with no water modification. When i kept neons before my water was considerably harder, with a tank Ph of about 8.2, it seemed in that water the neons were uniformally turquoise instead of blue. Anyone else noticed this?

 

[tstenback]

Have noticed this myself at times. Last night i was looking at mine and found that although all have been in the tank the same amount of time (1.5 years) there are some with solid blue stripes, some with turquoise stripes but most change depending on the way the light strikes them. Why?

 

[JamesTasker]

I think it depends on the angle you are looking at them and where the lights are in comparison.