The Oklahoma Aquarium http://www.okaquarium.org/ was a nice place to visit while my family was passing through Oklahoma. This aquarium is located near Tulsa in Jenks, OK.
From what we saw of it, it wasn't the largest aquarium I'd ever been to, but my family really enjoyed seeing the fish, seahorse, sharks, turtles and all the other marine animals.
There was a huge tank of sharks that was interesting. I think the guide told us 15 sharks were currently inside the tank, but it started out with a few hundred sharks (if I remember correctly). We walked through the tank's tunnel and the outside of the tank to see different angles of the sharks.
Also there was an open pool-type area where stingrays swam. At certain times I believe you can touch the stingrays (when we were there touching was off-limits).
There was a turtle area where you could pay like $5 or so to feed the turtles. We didn't do this because there was only about 2 pieces of food in the very small cup, but we watched a little boy feed them. The turtles climbed over one another trying to reach for the food.
This aquarium had lots to see. Pretty fun for kids or adults even to get a little lesson in fish and other marine animals. The cost for an adult is currently $13.95 and children ages 3 - 12 are $9.95. Oh, and under 3 are FREE!