IME, Bristlenose Plecos are more efficient algae eaters and seem to target a wider variety of algae than Otocats. BN plecos also seem hardier than otocats, at least that is based on my experience and first hand observation, take it FWIW. Otocats are excellent diatom algae consumers, but I found they always go into a deep depression(3 days or longer) and sulk and pout after the diatom algae is gone. Sometimes, they will snap out of it as hunger seems to get the best of them and will grudgingly start feeding off zucchini. Sometimes they just will not feed off zucchini or even algae wafers and will madly and continually(in desperation) check out the tank walls in the hopes of finding diatom algae. I have had tanks where there was no diatom algae, but different types of algae(green dust, black brush/black beard, thread algae, hair algae) and the otos did nothing but sit on a plant with eyes focused on the algae with a dazed and confused stare. They rarely would even move and graze on the algae. With bristlenose plecos and even Siamese Algae eaters, it was different. The bristlenose pleco would not touch Blue Green Algae or even Black Brush algae but would graze on the other types of algae. The Siamese Algae eater would graze on the BBA and other types of algae, but not the BGA.