The disappearing guppy spot?

[jyanagi]

Is this normal or do I have mutant guppies?

I have 2 male guppies who under normal circumstances have gold bodies. Each morning, I notice that they both have a dark blue spot on each side just in front of where a female would have a gravid spot (they are definitely males). Later in the day, the spot will disappear.

This evening, for the first time, I put these two males into the female tank. In addition to immediately courting the females, this spot became very evident. The larger of the two had an additional blue spot appear at the base of his tail (also both sides).

In the past, I have seen these and a 3rd spot 1/2 way between their head and anus. They all come and go, but the spot I first mentioned is the most common.

These guppies are the color of their mother (gold), but the spots are the color of their father (navy blue).

So, is this normal or is my water radioactive? Has anyone seen this before?

Thanks,
John

 

[Ghost_knife]

could be a stress thing. if it just after lights on they may stress. no worries about them. they should be ok

 

[psilo]

Perfectly normal. The spots will become much more evident as they display either territorially or sexually just in the same way any fishes colours can be enhanced and fade given stimulation.