Re: shark attack
A Barracuda, which is basically a swimming mouth with lots of sharp teeth, will generally not bother you.
However, when under them near the surface, if the Sun glares off your mask.........watch out.
They can accelerate from dead-still to a trebillion miles per hour in 1 nanosecond and they WILL strike at your mask.
I know about that too (and Green Morays, Sea Snakes, Turkey Fish, Lion Fish, Fire Coral, those black Urchins with lots & lots of very sharp quills, etc.).
And, Boy, do I have a story about a Green Sea Wrass that'll have you in stitches.
Been a long time since I've been in the water but with almost 1,000 hours of bottom time, there's a lot to tell. Some of it's pretty darn funny.