Hi Michelle,
There is no place in Galveston (or on the Texas Coast that i'm aware of) that has dolphins. I recently began working at Moody Gardens and let me tell oyu, that place is great. No dolphins (very difficult to keep in captivity). But the Rainforest Pyramid is Awesome, make sure you go through slowly. Every day people come up to me by the Ocelot (his name is Ozzy) Area and tell me how bored they are. You have to remember to look up, there are many exotic species of bird in there and many endangered species that we may never see again in the wild. The Aquarium Pyramid is alot of fun aswell. Our Carribean Tank is 800,000 gallons, complete with Sand Tiger Sharks, Brown Sharks, a Laggerhead Seaturtle, penguins and seals as well.
As far as seeing dolphins goes, you can usually see them on the Free Ferry from galveston to boliver. Exit your car and stand on the upper deck, you get a great view of th entire bay and can usually see quite a few Porpoises (sp?). On several fishing trips i was swimming afterwards in west bay (from the boat) and there were several that were curieious enough to nuzzle into me and check me out, they are magnificent animals. I hope you enjoy yourstay.
(I didn't mean to sound like a MG commercial, i really enjoy my job.... most of the time)
Brian