Honestly, otos are very sensitive. If they live for a month then you'll have them for a while. All otos are wild caught and go through the stress of shipping and having no food during transportation and rarely any food at the pet stores. I had one oto live out of 9 and I had him for a little over a year. He died recently due to a terrible ich infestation. Still, it really depends on the stock and the food available. Otos mainly eat brown diatoms and they can form within an aquarium within a few weeks of setup.
100g Native Fish Pond, 55g Goldfish/Catfish Community, 50g Plant Pond, 40gB Tetra/Cory Community, 20gHM Community, 20gH Turtle (Bender [RES]), 20gL Turtle (Kif [YBS]), 15g Reef, 5.5g Betta (Okami), 5gFBH Betta (Pron), 5gHex Betta (Twister)
2 dogs, 13 cats, 2 turtles, 1 bearded dragon and 1 crested gecko