Wow, I can't believe this. Less than 24 hours in my tank, and I swear I'm seeing spawning behavior.
Watching the fishes just a moment ago, it looked so familiar. The pair of serpae tetras going back and forth through the anchored apono capuronii leaves, one was doing this familiar wagging motion with its pectoral fins and when among the foliage there's a second where they press their sides together and quiver in unison. I'm pretty sure that fin-wagging motion is the male courting the female- it looks just like the attention-begging gesture my male cherry barbs make towards the females.
I kept an eye on them, and when the pair passed close by the serpae with a missing eye, the one who'd been fin-wagging paused cruising with its partner to position its body stiffly broadside to the weaker fish, and buffet with its tail strokes. I'm fairly certain now that pair is male and female, and the one-eyed fish is another male. Who is quickly becoming the pariah. I gotta get more of these fish. And move them into my main tank, soon.
They must like it here already, and I sure know it's not really an ideal tank.