Fish did all the work
Of fish, the tank houses 2 otos (that I can't catch to transfer to my oto tank), a male betta and 4 CPDs (2males, 2fems). I'm pretty sure they're not oto babies, lol. I've been feeding the CPDs blackworms and they've been very frisky lately, the fry also have the same swimming pattern, so I assumed. BUT if they somehow came in on the plants people have been donating (for the classroom tank), then I have no idea what kind of fish they'd be.
The boys doing their boy thing: