Hi all,
"Ordinary" Otto's are now bred in huge numbers in Singapore, and that is why O. cocama is much more expensive, they are still wild caught. O. affinis is quite a rare one in the UK, the ones you usually see are some of the O. hoppei, vittatus, vestitus persuasion.
I think of them as little Gold Nugget Plecs, and treat them like they cost £20 each, they need very good quality water, highly oxygenated and they don't like temps much above 26oC. as well as feeding with cucumber, courgette, blanched runner-bean etc. LFS are really poor at looking after Otto's, they are very sensitive fish, I wouldn't suggest buying them from any chain you need to try and find a store with a proper fish keeper in place, where they feed them vegetables etc. and only buy them after they've been in the shop for a while, so the initial die off after transportation as occurred.
I'd also be wary of keeping them with CO2 injection, unless you could ensure really good oxygenation at all times.
Quite a few people have tank bred them in the UK now, the trigger appears to be keeping a large number and/or keeping them with a (similarly marked ideally) dwarf corydoras species. They are definitely long-lived for a little fish, my oldest is at least 4 years old. I have 4 in the tank in my kitchen, and I hadn't seen 2 of them for almost a year until recently when I turned the light on (after all the tank and kitchen lights had been out for a couple of hours), as they become almost entirely nocturnal as they age.
cheers Darrel