I currently have a 110 gallon aquarium with two cortez rays which will be upgraded to a bigger tank or indoor pond. I haven't decided on the dimensions yet but it will be a few hundred gallons. Anyways I was looking to add in something else to add a little more diversity and character, but I really don't want to add live rock to make maintenance easier. I'm open to any possibilities and some things I was thinking about was a marbled cat shark, horseshoe crab, batfish, archer fish, scats, look downs. I don't know for sure how any of those would do with them or if they are fine without rocks, and if anyone else had ideas I'm open to anything.