Molly fish question breeding

My molly fish JAWS has been chasing around my one platy. JAWS is the boss of the tank.I think I see him trying to do it with the platy. When he wants to do the act, his top fins stand up straight and his color, he a Dalmatian molly but now is more black, shines very colorful. Greens, white, and black. He is so pretty. Then a few seconds later all is quiet again. The platy really does care and when that is all finished the platy goes back and hangs with her other mates. They do this mainly in the early evening.
I haven't heard about cross breeding fish? Do you think that platy will have babies from a molly?

 

Hi, welcome to the forum! Mollies and platies can't crossbreed. They might try to, but it won't work. It could just be the molly bullying the platy too. In my experience, mollies can be pretty aggressive and territorial.

 

Platies can interbreed with swordtails but not mollies. I believe mollies can interbreed with guppies.

 

Thanks all. So what is with his top fins up. Just letting it be know he is the boss?

 

Thanks all. So what is with his top fins up. Just letting it be know he is the boss?

That could be why. I can't really think of any other reason as to why he'd "flare" at the platy. Again though, the molly might still be trying to mate so that could be the reason also. Either way though, I don't think the chasing and "flaring" is anything to worry about unless he's constantly bugging the platy and stressing it out.