Various sea creatures in tanks inside (check out the electric eel) or outdoors - At one time, you used to be able to buy food to feed the penguins. There are shows with the seals. The new Belize reef exhibit that opened this July is cool - moray eels, sharks, and sea life in a coral reef environment. Something for everyone - walruses, jellyfish, etc.
$12/adults, $8 for seniors and children, parking is another $8 so this can really add up but you could spend the whole day here, so much to see and do - bring snacks and drinks with you to defray costs. If you have about $300, you can even have a birthday party here.