Cayman is sick!
He was swimming happily yesterday morning. By the evening, he was on the bottom, tilted on his side.... I treated him with some Epsom salt, and covered his tank with a towel to keep it dark.
This morning, I lifted up the towel, and he was floating on the surface. I was sure he was dead.
I tried to scoop him into his cup, and he swam away! Yay, he was alive! Sick maybe, but still alive.
I did a partial water change, again using Epsom salt.... Tonight, he still hasn't pooped, though. I'm still fasting him, and peeking in through the towel. He seems to have trouble with his buoyancy.
But at least, he's still alive. So there's hope.... I'll keep up with the Epsom salt treatment, and keep on hoping....
My other guys, Fiji and Tahiti, are oblivious to what's going on in the other tank. They watch each other through the sides of their tanks and flirt.

I'm really glad that they're still healthy.
I think my 3rd tank is jinxed.... Or maybe it's contaminated. I'd washed it with bleach solution after Little Fishie died. But based on what I read today about the 'blue betta mystery disease,' it may be a form of Mycobacteria, and bleach may not be enough....
I've just washed my 1 gallon tank with bleach, then sprayed it with Lysol, per the Mycobacterium cleaning protocol. Tomorrow, I'll wash it with 70% alcohol, then rinse well and let it air dry. Once I know it's clean and free of bleach, Lysol and alcohol, I'll transfer Cayman to it. (Notice that I'm assuming he'll still be alive!) Then, I'll take his 3 gallon tank through the same cleaning protocol. I'm considering tossing out his silk plants and decorations, and buying new.... (I prefer not to consider that his illness may be due to Mycobacteria. There's no cure for it.... His symptoms are different from what LittleFishie had though, so I'm remaining optimistic...)