I picked up a couple oto fish (one didn't survive so I only have one) for my 28g Euro bowfront tank last week. It's doing a great job cleaning up the algae that has thickly accumulated on the side of the tank. However, there is poop all over the bottom of my tank now. What's the deal with these otos? I'm hoping it doesn't create an excessive bio-load, requiring me to do water changes more than I needed to before.