Originally, I purchased four otocinclus to eat the diatoms that were growing in one of my tanks (it receives a lot of natural sunlight from my window).
However, due to some unprovoked violence from the original inhabitant, I decided to place them in a 20 gallon tank that had a lot of algae growing on the wood and glass. It houses a very peaceful wild betta female who spends much of her time hiding under a log.
Unfortunately, one of my otos sadly passed a day after I received it (was sent from interstate) and the other three had started doing this erratic swimming and twitching so I assumed they were on their way out too. I adjusted the flow on the filter to increase aeration and did a quick water change, but decided to leave them to their own devices. I chalked it up as an expensive lesson learned and vowed not to waste my money when a toothbrush and scraper would do.
You can imagine my surprise when I went down there to check on them and all three had chewed their way through a massive amount of algae. It took me a moment to realise that the hundreds of pellets scattered through the substrate was their poo. I never thought such a small fish could poo so much. It rivaled even my goldfish.
The tank they're living in doesn't have much done to it. The temperature is around 70-72 Fahrenheit and it gets two 25% water changes a week. The pH is around 6.0 and I have no idea what the parameters are. Yet my three otos have finally settled in, and are now as fat as ticks. I can see why shipping is so hard on them as they really need a constant supply of algae to feed on.
They definitely make for a great clean-up crew in established tanks.
Anyway, feel free to share any oto-related stories here. I was just amazed at how industrious these guys are. Although I think that I might have to do some more gravel vacuuming if that's how much waste they produce on a weekly basis.