Fish typically don't seem as likely to harass algae eaters/bottom feeders as they might other types, although it's good you have a back-up plan, as a problem might require a very prompt solution.
As pointed out, other fish need to be settled in the tank prior to the addition, or re-addition, of the betta, as this makes a massive difference to his perception and acceptance of them.
Actually, speaking as a non-expert, and stating an opinion based on personal experience and reading only; while this is excellent advice given above and a mature tank running 6 months to a year may be ideal, it would seem, at least in my case and some others, that stable, well-planted conditions and an algae supply will do.
(However, the tank in which my original otos were first placed was set up in the path of light of two different sets of windows, and only the plant mass prevented really annoying algal overgrowth.)
I'd also like to point out that although 6 or more otos may be ideal, this can't always be managed, as it's recommended that 5 gallons be allowed per oto to ensure adequate algae, so that this would prevent anyone unable to manage anything under a 30 gallon from having any.
Honestly, I think they're better off in a planted tank with suitable algae present (they can't rasp off things like hard green spot algae and need the soft, green stuff - I leave lights on extra-long in their tanks to encourage growth of this type) than quite possibly starving in a store tank with none.
Otos have a reputation for being delicate, however they're apparently often captured roughly/with the use of damaging chemicals prior to suffering stressful shipping and typically are then placed in a clean sales tank with little or no suitable food - little wonder the poor little guys apparently often don't make it.
I suspect the first otos I bought were tank bred, as they were hardy little guys, and I'm glad I didn't hear about their supposed delicacy until a year or two after purchase - even then it made me nervous, although they'd been fine throughout the time before I'd heard this.
I bought three skinny little guys from a pet store to join the survivor of that pair (after some months nailchewing wait as I was unable to figure out why one had abruptly died and needed to ensure that the other wasn't at risk or contagious) lost one of these who clearly wasn't doing well and, sadly, never even tried to feed, although the others steadily livened and fattened up, and recently bought 5 big, beautiful, healthy otos from a home basement-store seller to divide among two tanks, so that I now have 5 in my 25 gallon and 3 in a 15.
I expect this may be considered cruel by some, although they seem happy enough, and the difficulty often encountered in getting otos to eat anything other than algae (one of mine will eat cucumber in a pinch, others seem to ignore all veg., although the newest otos eat spirulina pellets the rest won't touch) is a bigger concern to me than the numbers, although I'd certainly love to have herds.
Of course, if the eggs and fry weren't apparently so tasty to other fish, I'd have tons.
It seems as though everyone breeds for party snacks...
P.S. - Amano's, as well as Cherries, will breed like bunnies, the problem is that the Amano young do need to be transferred into salty water...
But there's also a look-alike version of Amano which can breed succesfully in freshwater, and I'd much rather have those myself.
And I don't see why those aren't regularly sold.
very nice
