aggression or mating??? is it a priority???

Considered one of my peas is chasing the opposite round, nipping at her, biting her, pushing her round, the other way up and to the bottom. I assume it's mating as a result of i've seen related earlier than however i'm scared he's genuinely hurting her, and it appears like she's lacking a fin. do i take her out, or him? or go away them?

https://cdn.discordapp.com/attachments/830976708307320884/1096899428062859414/IMG_3683.mov

https://cdn.discordapp.com/attachments/830976708307320884/1096899451265749192/IMG_3681.jpg im undecided if these hyperlinks work however please let me know, i'm fearful