color changing guppy?

[CT_]

My guppy likes to change color some times.  it usually has a light colored body but sometimes it gets almost black in a patch.  Anyone know what this is about?  I know fish can loose color pretty fast if they're freaked out but this guy can turn it on and off in really short order.

These two photos were taking 30 min apart.

30 min later:

[Fish Folk]

Interesting. Do you think it is stress-related? Is there a relationship between first lights-on and the black patch? How are your parameters? Would you say the fish has always done this? Or more recently? If recently, was it normally black-patched, or light-body colored?

[lefty o]

mood, hormones, lighting. they all play a part in fish colorations. id likely not be too concerned unless he went pale, and stayed pale.

[Koi]

My guppies do the same thing and I always attributed it to mating displays. When I feed or after a water change my guppies colors flash like crazy. Ive noticed the same thing when I add salt or minerals to a tank.

[CT_]

Same guppy looses its yellow if something is wrong.  His "default" is no black but the black comes and goes seemingly randomly.  Those photos were 4pm and 430pm.  pretty centered in their photo period.  It's the blackness thats so "alarming".  I've heard of loosing color but gaining black is weird 😉

[Koi]

I have a guppy that has a black spot at the base of its tail (similar to an oscar) and a guppy that looks very close to yours. Both of their spots get really black.

I could be wrong though, I've just never paid it any attention. Hopefully I haven't been killing my fish this whole time...

 

[Tory]

13 hours ago, CT_ said:

Same guppy looses its yellow if something is wrong.  His "default" is no black but the black comes and goes seemingly randomly.  Those photos were 4pm and 430pm.  pretty centered in their photo period.  It's the blackness thats so "alarming".  I've heard of loosing color but gaining black is weird 😉

This is purely speculation but I would guess that if his default is the paler color and the darker coloration only shows up sometimes that it's a mating display. My males definitely get more contrast in colors when they're showing off for the ladies

[CT_]

1 hour ago, Tory said:

This is purely speculation but I would guess that if his default is the paler color and the darker coloration only shows up sometimes that it's a mating display. My males definitely get more contrast in colors when they're showing off for the ladies

It's funny I've got 3 males and the two with long fins spend all their time doing what I assume macho fish stuff.  There's never any biting but they chase each other back and fourth and do this weird sideways shaky display at each other.  The irony is when I introduced otocinclus into the tank one of them chased the guppies away so I think they're actually big softies.