otos are about the best you can do for a 10g, any pleco would get too large. However otos can be a bit sensitive, and I wouldn't add them until the tank had been set up and clear of any problems for at least a couple of months. They do best if there is algae in the tank when they are introduced, sometimes they can be a bit slow to normal fish food. I personally would go all guppys some of them are so pretty!!