Also, otos are fast and smaller than bettas so they need small hiding spaces that they can go in if the betta decides to chase them. They very rarely eat wafers, and its hard to find some that eat anything. Most die of stress from shipment etc. And as well as they need a 10 gallon tank, but its worth it for the betta and them.
A huge factor is that you have to have a steady amount of algae in your tank. Since they are shoaling fosh they have to have more food. If yo domt have algae but want otos, take some rocks/decor and put them in a container filled with water and set them on the windowsill or outside. Make sure you always have more with algae in case they eat all of it off the other rocks!
Snails are easier but some nettas wont tolerate them, and will comstantly peck at their shell trying to kill them. Thw snail will eventually die.
IMO I love otos because snails are the norm and some snails such as pond snails are super invasive and all snails can mate with themselves so even if you start with just one you might have a lot in the future! Also, some snails are semi aquatic and sold as aquatoc so if you end up with one ofthese you need to slope the substrate at one end of the tank so they have some land. They dont need much, maybe 2-3 inches across the side.