Grab yourself a pair of flippers and face mask/snorkel and get started, Aldi's are good enough for starters and will have some for Xmas. Paint some eyes on either side of your flippers, it does work, as the "bities" like coming from behind and tend to get confused. Always dive or surf with a mate, improves your chances by 50%, :) unless you know your territory. Always smear the inside of your mask with some detergent or shampoo and rinse, this is guaranteed to stop "fogging". You don't need "lungs" (air tanks) as they limit you to 30-40mins. on average, whereas you may want to cover a lot of area and can spend the whole day diving in comfort until you get tired and most fish and coral etc, hang out in shallow water 5 -20ft. If you don't know the area or territory, check out where you will get out and if there are any strong currents with change of tide etc. Once you get started you'll end up with a gun or camera. I have always used a pronged head and always head shots or just behind the eye for instance kills for obvious reasons.. My Olympus Tough Camera has given me some interesting shots, and no problems in 10yrs., always soak any camera in fresh water for 10-15min. after diving in salt water, as when salt water dries the grains of salt may form around or under the camera's seals, thus resulting in leaks. etc.
Also the whole family can participate and enjoy..