yeah pleco would most likely eat eggs if dempseys arent diligent enough, but also plecos get HUGE depending on the type you get the typical pleco at most lfs will get really big and they help with algae when they are little but when they get bigger they are pretty much just poop machines so dont help keep tank clean at all except to maybe eat algae from driftwood or something i would def go for bichirs and not pleco (they aren't as messy and are more fun to watch as well)