The Main thing is not to wake him up

...so, when you are doing the spearfishing in the places where the Croc's are sleeping, the main thing is not to wake them up! You may even pat him slowly, but I'm not sure that he'll love it.
Moreover, his eyes should be up the surface , than you may do spearfishing under his belly. At the same time you should be aware of sharks..
The rules of spearfishing during their presence:

• don't pat
• if you pat, it sleep like a log
• the eyes should be up the surface
• don't think about future
• be ready to race with obstacles
• make a will just in case