Thanks, is it the UV they need from the sun ?
As none of mine have had UV up till now but all of a sudden my two males have started to darken, having said that they aren't getting the same amount of chicks as they used to, so maybe thats why.

Have had to move them into tubs as after floods here I can't move back into my house so at a friends house. When I get the room sorted then I can get them back in vivs again. I miss watching them all the time.

Mike