Been dosing Hikari CyroPro every week now. Sometimes it looks like these things--whatever they are--are gone, but then a few gradually show up again.
He's still got clamped fins and has been dealing with fin rot. I treated daily with Paraguard and aquarium salt with water changes (starting May 25) and today stopped both and started with Microbe-Lift Artemiss. It's hard to tell if his fins are getting better or not.