I think it's more of a personal call. If it wasn't just out of curiosity would you want to risk the ray? If you would risk putting them back in do you think the ray would be healthy enough. Honestly I don't know your fish like you do so I don't know how they might react. If it were me I would probably put them in and keep them well fed for the first few days to make sure they don't even think about taking a bite out of the ray. On top of that I would keep them on a short leash so if you notice any aggression or more curiosity I would instantly pull them out.If you want to put them back in your best bet is to feed them very well and give them no excuse to even try to take a bite out of the ray.