One of my 3 ottos died this week. I doubt they can ever eat too much algae, I was a little surprized that mine died, but considering that my guppies are getting old and I have to bury 3 at once sometimes, and considering my past experience with otos, I was not very surprized. My oto that just died recently died right about the time I did a water change, so maybe it was stressed. They've also eaten most of the algae in that tank, so I might at least move in some furniture from another tank with more algae. I could move the ottos, but i think the only tank with much algae right now is the goldfish tank, and they would be easy snacks in there. I'm happy that I at least still have 2. I think this is the longest I've kept them. I think I got them during winter break. I have been throwing in algae wafers once a day, but usually I just find them clustered with snails the next morning.