In 2006 I did the shark feeding with the Beqa Adventure Divers. It was a great experience and you are able to spot bull sharks, tiger sharks, nurse sharks, all sorts of reef sharks and other big and small fish... To be honest I never seen so many fish at once... The company supports the protection of the lagoon and the sharks. Book one-two weeks in advance because it can be quite busy and they don't feed them every day. After the dive you can buy a great video of it. I still remember the dives it was such a great experience.