@irThumper: Good, common sense answer! Luckily Bonk was willing to eat about four medium size dubia last night so I think he's set for the weekend. I may leave Julep in quarantine if Bonk doesn't get much next week though.

@Lynn: I wish I could send some spring your way.

Bonk hasn't lost a tank-mate, not recently. He was in a Petco tank with other frogs back in September, but he didn't show any ill effects from leaving. He's always been a little skittish. I think part of his slowness to eat comes from being tong-fed a red wriggler once. He's never trusted me since.
I will get a second thermometer. Bonk's been warming himself up by sitting on the ledge directly underneath the heat emitter so maybe the rest of the tank gets a little cold.