I have yet to find a place in Egypt where big animals are not a scarcity. You will spot a whale shark or similar only if you're lucky once in a lot of dives. Some go years without. So for big animals I will choose not Egypt.
Dahab is excellent for reef & reef fish. As a photographer I enjoy Dahab macro very much, but need to know what to look for.
Most of the time for photos I spot medium sized marine life: octopus, barracuda, morena, turtle. Very common.
Last visit we went to find a giant morena living near the Mashraba bridge. Here is a photo from my phone.
Oceanic Whitetip Sharks are pretty common in October-December in a few locations. Hammerheads (groups) used to be fairly common in summer on off shore islands, particularly off Deadalus North.