I have had a bit of push back in the past online with my thoughts on otos, but I still stand by it.
In short, if you're buying otos, buy double the amount you planned on. They die heavily, well that's not always true, but you should expect some not to make it. Otos species get mis-sold all the time, you probably do not have O.Affinis.
Even when buying really healthy looking fish, some will drop off. I think most of the damage is done in collection/transit.
Otos will come round to eating vegetables, but to encourage it house them with other algae eaters, Farlowella work really well here. Otherwise your weaker plants might get damaged.
They're very hardy, once the weak have died. I find them to look more comfortable at 22° than 25°.
I have 7 otos in one of my tanks, it's a jungle I admit. I bought 12 for that tank, sadly. They did spawn, but nothing came of it. Maybe I'll put a bit more effort into them later this year.
Also, good article.