Its touch and go. They will grow at diff rates so it would be best to start with adults im guessing. If you got youngfish you may have a problem when aro gets 16 inches in a year and the dats are aropund 6 to 7. But it depends on the individual fish and size of tank. Some aros wont bother any neighbors. My aro wont let anything share his tank. I have tried dats and rays. I ended up buying seperate tanks for them. All this being said, there are many ppl that keep this combo together. I cant promise it will work and i cant say it wont. Just be prepared if it they cant live together.