Thanks, CoopChick and Quailtrail. I have the wazine in the water today and am trying to entice them to drink plenty! This was definitely a roundworm. Have been doing a lot of reading on wormers. Although I didn't want to, I have a feeling I will likely get into a 2x/year schedule. After the first dosing of wazine, I'll probably switch to a broad spectrum.
I jinxed myself, because last week I was noticing how good everyone looked and was acting. Then this week one of my rocks started keeping her tail down... in my limited experience that is always the start of something bad. It wasn't her, but another rock who pooped the worm. From what I gather, by the time the worms come out, they already have a big load of them... I hope I'm not too late. Wonder if worms are what killed my other rock last month.