[Shadowkiller]

FL 20 = Strobe?

Unless you intend to chuck a wideangle or macro lens on it, you wont really need a strobe as such. The internal flash does a fine job, its just that your aperture and exposure setttings aren't as high (or low) as is possible with a strobe in tow.

Mind you, a lot of scubbies have an obsession with photographing things that dont move... Whereas I like to hunt fish, a situation where the lack of strobe gives me an advantage due to increased manouverability.

Just take your cam and housing out and go nuts. Shot everything and anything. From every angle conceivable. Its the bets way to learn. Then, if you'll be in a much better position to judge what kind of strobe or additional lens you might need.