I have had my female in a 29 set up for her for about a year now,( completely closed top) and just got a male yesterday. He is in quarantine, the female looks to be gravid again. I was cleaning the tank in November, and found around 100 eggs that had been deposited in the gravel, and under a resin rock ornament. The eggs were very adhesive, and there was also a fair amount of "glue" holding the gravel together where they had been laid.
I had been feeding live ghost shrimp oocaisinally too, but the last ones all died before they were eaten. I had been keeping several transcriptus in the tank, so it may have been them, not the eel, that was eating the ghost shrimp. She is fed frozen bloodworms daily, and frozen brine shripm at least once a week. I recently changed from brine to mysis shrimp, since they are supposed to be more nutritious. She seems to prefer the bloodworms, and had been eating flakes when I got her, but is now spoiled from the frozen food.
Several people have had the elipsifer eels looking gravid, then be thin again a day later, but no eggs or fry have been found. I suspect that I happened to find the eggs very soon after they were laid, because they took several days to a week to fungus. Seems a long time, considering none were fertile. I plan to move the paracyprichromis out of the 29, put in the male after he's cleared quarantine, and cross my fingers. Once they spawn, I will move them both to a 55, leaving the eggs in the 29 to hatch.
I found an article published on spawning the peacock eels, they lay eggs in plants, but the tang eels do not. Otherwise, I would expect the information to be close to what to expect from the plagiostoma eggs. They hatch after several days, the fry are tiny, feeding on infusuria, probably for about a week. I'm hoping by then, they will be able to eat baby brine shrimp. Given the published hatch/survival rate, it seems unlikely that more than 25-30 will survive the first couple weeks. The fry look like most other fish fry, developing into eels as they grow. The good news is that they do grow rather quickly, compared to african cichlids.
I figure an established aquarium with a couple of sponge filters should support the fry well enough until they are big enough for baby brine. I have N. gracilis cichlids in a 38, they produced around 100 fry, none starved to death before they were large enough to eat food larger than microscopic stuff. I just hope the female doesn't deposit eggs again before I get the male into the tank with her. In the lake, the spawning season for eels is November-March. I asked an aquarist who has a group of elipsifers about multiple spawns during the season, and he confirmed that the females do become gravid more than once. At the rate my female is going, I think she may produce at least one more spawn this season; it's been almost two months since the eggs, and she looks very fat again.
I read somewhere that one species of tang eel does take care of the eggs, fanning them, but it wasn't a plagiostoma. Obviously, the elipsifer's don't care for their eggs, neither do the peacock eels. I believe the best bet for raising any would be to remove the adults as soon after they spawn as possible. It may also be better to separate the sexes for conditioning, many other tropical fish are handled that way. Elipsifer's are sociable among their own species, but they seem to be the exception.