Color-changing Guppies

[FancyGuppie]

I have also got Fancy Guppies whose tails are changing color dramatically. Two from the same (?litter) both had brilliant yellow tails, one stayed in my main breeding tank which is a planted tank (and therefore gets higher variations in nitrogen levels at different times of day/night), for that one the yellow shrunk back to halfway and it got a row of spots on the outside and the end changed to a rich orange, it happened all on one day. The other one I moved to another tank and the tail remained bright yellow. I moved the latter back into the other tank last night and now all the color has gone and spots have developed. This does kinda suggest to me that the water conditions and the stress of moving / changes do affect the color quite a lot.

 

[FancyGuppie]

Update - The color has come back to my Yellow tailed Guppy and I have discovered another one I thought must have died that had a yellow leopard spot tail has changed to a pale blue and is doing fine!! This color changing thing is pretty cool.