I want to see the whale sharks, but keeping them in a tank is really stupid.
'Whale sharks feed on wide variety of planktonic (microscopic) and nektonic (larger free-swimming) prey, such as small crustaceans, schooling fishes, and occasionally on tuna and squids. Also, phytoplankton (microscopic plants) and macroalgae (larger plants) may form a component of the diet. Unlike most plankton feeding vertebrates, the whale shark does not depend on slow forward motion to operate its filtration mechanism. Rather, it relies on a versatile suction filter-feeding method, which enables it to draw water into the mouth at higher velocities than these dynamic filter-feeders, like the basking shark. This enables the whale shark to capture larger more active nektonic prey as well as zooplankton aggregations. Therefore, the whale shark may be more dependent on dense aggregations of prey organisms.' http://www.flmnh.ufl.edu/fish/Gallery/Descript/Whaleshark/whaleshark.html
When I worked at the Shedd, I helped feed our paddlefish. The eat a LOT of phytoplankton, brine, prepared krill, etc. And they are 1/50th the mass of a whale shark - at most.