I've kept stingrays before and never had a problem with mixing them with catfish or other bottom dwellers but I'm curious if they'd be okay with Geophagus? In the near future I was hoping to perhaps house a group of Geophagus Winemilleri or Abalios with one of the smaller rays like Hystrix. Now most of my wondering is due to the rays shedding their barbs and the Geo's constant "earth eating" and my use of a sand substrate. I've never had a problem with other bottom dwellers and rays but then again I've never had a fish that mouthed the substrate on a regular. Thanks in advance for any help or personal experiences you can give me.