I've heard that stingrays n green severum can be put together has anyone done this or know it's true. Just a big risk to try it so best to find out more information on this matter. Thanks to anyone that can help
They coexist in the wild (depending on the species of ray). Severums are usually tolerant of larger tank mates, but I'd worry they might pick at the rays eyes. How big of a tank?
Tank size is going to be what matters here, IMO/E. I haven't personally kept rays as I've never had the space, but I have a few friends that have. One of my friends has severums in with her three rays and doesn't have any problems, but she has a 300 gallon tank. Another friend of mine only had a 125 gallon and found it didn't work so well as her male ray decided he wanted to snack on the smaller severum.