Poop was runny on the cornuta. No skin lesions. Just went and checked him. He's dead. He looked like he had air bubbles in his stomach (his belly skin is translucent apparently. I could see the bubbles. He always ate good, but not as often as the other Cornuta.

I probably let the peppermints substrate go too long (3 weeks).

The only other thing I can think of is I.added some spring tails to all my cages about two weeks ago.