I think I'm spoiled by the National Aquarium in Baltimore which is truly spectacular...but the Dallas Aquarium offered an intimate experience. We went late in the day so we had about 2-hours to spend. It's always cool when the birds are free-flying. I wish more of them could spend their time like that. We enjoyed the giant otters and the penguins. The flamingos squabbled and honked at each other while we watched. The turtle and the manatee kept bouncing off each other in an underwater ballet. The sharks floated by in a menacing manner.
The only real complaints I have is that if the woman in the "last" gift shop hadn't pointed out the shark tunnel, we probably would have missed it completely. And I would've liked it if the exhibits had the names and pictures of the fish and animals on the wall or something other than those digital "interactive" displays that really only two or three people can use at a time. Granted, you get a map with your admission, but we probably lost ours in the bathroom about 1/2 way thru the building.