Stingrays and sharks can do just fine in home aquariums, the problem is the majority of people that purchase them do not provide proper care (this includes tank size). I do hope you have provided this ray with a properly sized aquarium and having worked with stingrays I would provide no less than 500g (they stress easily if they feel constricted). This particular stingray is considered hardy, but does spend much of its time waiting for prey instead of searching for food. It will eat small fish and crustaceans, but if it is not eating right away try live earthworms and ghost shrimp. Some fish can be harmful to rays such as angelfish, triggers, pufferfish, etc.