Thanks so much, Pete. VERY helpful.
Assuming this happens again, I’ll pay more attention to yours (and Nigel’s) advice about not exposing them to air. I had planned (after reading Nigel’s comment) on just using a small cup, but your suggestion of a turkey baster is amusing; I may try that.
Alas, while I saw upwards of 20 babies the first morning, by 24 hours later I can no longer spy a single one. Doesn’t mean they’re all dead, of course. I have tons of live rock and caulerpa, and the little guys are so small that a bunch of them could easily be hiding in places I can’t see. I may need to wait a few weeks and see if any survived to grow large enough to spot.
In any case, thanks so much for the advice. If this is really going to turn into a monthly event, and I find 20+ babies each time, it sure seems like I’ve got a chance of eventually growing a few new youngsters, even without a separate nursery tank.
I guess my final question is whether there is anything simple I could do to improve yield. In particular, what preys on baby seahorses? Like any typical reef tank, mine has bristleworms, hermit crabs, brittle starfish, snails, aiptasia anemones, along with the adult seahorses. I suspect the aiptasia might eat some babies, but I’m already trying to limit them for the sake of the main reef tank, so that doesn’t matter. Are adult seahorses cannibalistic? Is it critical that I remove all the babies into the refugium? It sounds like the London Zoo actually raised them in the display tank, which seems like a surprising success. Might cleanup crew like bristleworms attack a small seahorse?
I’m not sure if there’s much I can do about it in any case. Can’t remove all the bristleworms, even from the refugium. But at least the refugium doesn’t have hermit crabs (dangerous to babies?) or snails (probably doesn’t matter). I’d guess that aiptasia is probably the biggest threat that I might be able to do something about.
Thanks again for all the info.