Yes there are slaughterfish, but they leave quite a bit of space for diving.

You can't swim out to the big rock, but there's a decent amount of room near the beach.
That line may be a bit pessimistic, too, as you can get to the smaller rocks to the west, but not beyond them. It was way off - map replaced. Now I'm starting to think I may need to place some
buoys (barrels?) to mark it, if they don't look stupid because they're rigid, rather than floating. posts - they're cheap and don't look stupid when they're static. Fleur got rather nibbled putting those out there. Slaughterfish are persistent fetchers.