I don't have any Oto's, but I do have cories. I've been thinking about the otos thoug, ad they actually had some in at our LFS last weekend. My BF and I are thinkng of getting a nice bing 29 gallon tank, and I think we'll be getting some if we get the tank up and running.
They do look like very neat fish though.
I'd get some ore info about food though. I'm not exactly sure about this issue.
Momma, you know you've got way too many fish in that tank, right? The most you should have in there is 5 - and no more ( because of the one inch of slim boddied fish per gallon of water.). You're overstocked by 3 fish and although it's running nicely now, things are going to get messy down the road. There's just not enough water space for all of them, ad no matter how many plants ad hidey.s they is just not enought territory for them. If you want 8 females in a soroity, you're going to have to take either 3 out and start another, or get a larger tank.
Please, if you want your fish to be healthy and safe and comfortable, either take a few out, or get a bigger, roomier tank.