Want to know a secret? You can dive in and swim with the fish at The Seas with Nemo & Friends Pavilion in EPCOT.
There is a little known secret about Disney called Dive Quest.
My hubby did this a few years ago and said it was amazing. There are a small number of sharks in the tank that he noticed swim in the same pattern over and over. Lying motionless on the bottom he was able to reach out and touch a black tip shark as it swam by. Here is a link to a photo taken of him while he was diving from inside the pavilion.
This is a 3 hr experience with approximately 40 minutes in the water that you will remember for a lifetime.
You must be SCUBA-certified and at least 10 years of age.
Since this is a little known secret the only way to make a reservation is to call (407) WDW-TOUR or (407)939-8687. Currently the cost is $175 per person.
If you are not SCUBA-certified but would like to swim on the surface and snorkel in the same 5.7 million gallon aquarium then Seas Aqua Tour is what you are looking for.