From the website:
Adult $14.00 (tax incl.)
Child (4 - 17) $7.00 (tax incl.)
Student/Senior $10.00 (tax incl.)
Annual Family Pass $50.00 + tax
Annual Adult Pass $25.00 + tax
Annual Student/Senior Pass $20.00 + tax
Annual Child Pass $15.00 + tax
Children 3 and under are Free!
It depends on your definition of "expensive." The aquarium itself could be considered small, but the value is found in its natural state. When you consider the cost of obtaining, caring for and releasing the animals from and into their natural environment vs artificial surroundings, this is a bargain.