You're not the first to suggest that. I do have other Metriaclima species in there - a Red Zebra and a Kenyi. Lip-locking fights were observed only once between the Cobalt (now in hiding) and the Kenyi. I thought only males did that.
No sign of injury, so I'll keep watch for fry...
Getting a photo right now is difficult without breaking down the rocks. I just did a
water change a few days ago. Maybe on the next one...
Interesting. I hope that's the story here. Great fish. I'd hate to lose him/her/it.