Our 5 year old son is obsessed with in his words: "Marine Biology". He has been since he was a baby, first word was fishy and could point out a fish at age 1 from 20 feet away [including say a 1/2 inch sized logo on some box in the grocery store].
We had his 2nd b-day party here and had a blast and we brought him again last night. Still in love.
It is really fun for those tha enjoy sea life. The tunnels are amazing, the playground is a great resource and the plunge ride is awesome.
It can be spendy but if you have a Happenings/Entertainment book they have buy one get one free admission coupons, making it much more reasonable. Our family of 4 went for under $30 including the Plunge Sub Ride.