Just blundered back into this thread, which re-awoke a long-simmering interest I had in getting another Jelly Cat to replace the one I had long ago...especially now that I knew what they were called!
A few months back my local aquarium fish importer/dealer got a small number of them in, while I was out of town for a short bit. I watched them nervously on his website until I got back, as their numbers gradually dwindled with each update. There were two remaining when I got home, and I quickly scurried in and bought one of them.
The little guy was around 6 inches or so at that time, probably a bit over 8 now. He went solo into a fully-cycled 75-gallon tank, no substrate, several pieces of pipe for hiding spots, giant sponge filter and a temp of 76F. A handful of clean Rosy Reds from my burgeoning breeding population joined him and quickly dwindled away, to be followed by a couple of small frozen smelt; within a couple weeks he was switched over to Massivore pellets. Apparently smelt are also a thiaminase problem, but I will continue to provide them as occasional treats along with nightcrawlers when I can get a few.
I had forgotten how much I like this species; I guess a lazy guy like me is predisposed towards fish that don't move around much. I enjoy dropping food in and watching him loom into view, gobble it up, circle the tank a couple times in case he missed a crumb and then slip back into his cave.
I have just started assembling the components of his next accommodation, which will be a plywood 6x2x2 footer for which I have managed to find a spot in my basement...my last tank, I swear! I would not consider keeping a fish of this potential size in such a cramped tank, but since he rarely does much I think it will work; I can always build bigger someday if I feel the need.
On a sad note: getting this fish prompted me to try contacting the fellow to whom I gave my original one during a move about 20 years ago. That fish was over a foot long when I got it; I owned him for a bit over 10 years and he was about 24 inches long when I re-homed him; I had planned to get him back when I settled into my new digs but the new owner fell in love so I let him stay. I kept in very sporadic contact with the new owner for the next decade or so, then lost touch about 10 years ago when I moved again. I recently was saddened to hear from mutual acquaintances that he passed away a couple years ago. A mutual friend helped his widow re-home all his fish and lost track of who got what, but she recalls that Jell-O (they christened the fish right after they got him...) was measured at 28+ inches (total length) when he left her care.
So the fish lived for roughly 28 years after achieving a length of about a foot (say...another year or two for that?) and was still a going concern when I lost track of it. That's my kind of fish!