False alarm.
First, my biggest female some how got wedged between a rock and the tank glass and expired before I noticed her missing.
Not long after, the male stopped visiting the cave he had been spending so much time in and lost the dark color except at feeding times.
Next, I recieved some rainbow darters which seem to be out competing the smaller tesselateds at feeding time. I just noticed yesterday the smaller tesselateds were getting skinny despite a ridiculous amount of food added to the tank. I realized I had changed my feeding method from target feeding around the various zones of the tank to adding all the food to the strongest current. I did that because the rainbows get right up into the strongest current and the various minnows and dace are close behind. I liked the natural look of it - seemed like the bottom of a real river. Last night though I realized all the smaller tesselated [including all the females] were hanging back in the much slower current and very little food was reaching them. They'd make forays into the current but seemed inept at grabing the food zipping by.
I'm gonna have to go back to distributing the food around the tank so everybody gets enough.
As far as breeding goes, I guess I'll have to decide if I want to set up a seperate "cool down" tank. Now that my furnace runs nonstop, tank temps in the river set up rarley go below 65 F.
I'm contemplating setting up a 20 long over by the bulkhead going outside from the cellar. I used to brumate native wild caught snakes there and it always worked good.