Jeez. I didn't realize such a negative reaction to otos.
I bought my otos as a complete beginner. I'm not sure what factors led
to their survival. They've been in my tank for a year (I'm knocking on wood now, because every time I say something good about my tank something bad happens...) I think I waited for my cycle to finish before adding them so as to not stress them. I had read that it's touch and go with them at the beginning, because of starvation during shipment, but that they seem pretty hardy otherwise.
I think I kinda increased chance of survival by purchasing them from a LFS
that had the same water parameters (and tapwater) that I did. I also bided my time after the shipment arrived so the weaker ones were weeded out. And I decided to buy the ones which looked most healthy with round, not swollen tummies. (Which happened to be the only two left
Also the LFS
was 10-15 minutes away, so they weren't in the bag long. I don't recall if I let the bag sit or if I dumped them in the tank right away.
The reason I decided to go with otos over a pleco was that I have a small tank, and I wanted as many fish as possible, which meant very small fish (I am well within the inch per gallon guideline). And they're really cute - plecos are kinda ugly. I also had read at the time that plecos are major waste factories. But then I've since discovered that otos are miniature poop factories.
They're really cute and industrious. I don't know if they scratched up my acrylic tank, but they may have. (I guess all suckermouth catfish have the potential to scratch acrylic, but I don't have this verified). BTW
I do supplement with zucchini now and then, because the tank doesn't have much algae. I sort of go by tummy size.
I don't know if this is helpful or not, but thought I'd relate my experience.