Strange blackness appearing on Creamsicle Molly

[Frozen]

I have had 1 male and 1 female creamsicle mollys and 1 male and 1 female dalimation lyretail mollys for some number of months now. The males are housed in a 10 gallon planted aquarium with various other fish and shrimp, while the females are in a 7 gallon non-planted aquarium with only a betta, 2 cory catfish and a baby molly in a breeder net. Everyone is doing very well except one guy. I feed flakes, frozen bloodworms every few days, and occasionally frozen brine shrimp with spirulina, which they don't really like.

(Healthy Female Creamsicle Molly)


Over the last few months my male creamsicle mollys back fin, the bottom half, has been turning black, while the top of his head look like algae is growing on it. (Red arrows pointing to)
I had a male creamsicle before that this happened to, and eventually it died, but from this fin blackness im not sure. Sorry these pictures arn't very good, its the best I could get after a million trys.



What is this? Is it life threatening? Can my other mollies and fish catch it?

Im a newbie here, so sorry if this post is to long! Any help is much appreciated! Thanks!

[Damon]

Looks like a color change. common with livebearers as they are so crossbread and interbred, unless you get from a true breeder and not from a lfs, you are not getting pure strains.

[Frozen]

Okay, good. As long as he's not getting sick or preparing to die. I can deal with a color change. Thats actually pretty cool. Thank you!

[DUSTIN323]

Yeah I think Simpte's right. I can't think of any kind of diesease it could be.