Steven Catron wrote:

> >     Buddy Alert
> What's this?  If you wanna alert your buddy to something, bang the pommel of
> your knife on the tank to get your buddy's attention, and save yourself some
> money.

The other day I was trying to attract Roger's attention to show him
the beautifully marked Fiddler Ray (Trygonorhina fasciata) that I'd
come across. He just wouldn't look in my direction.

I waited until he'd stopped exhaling and yelled "Roger" into my reg.
He heard me no trouble at all. It works for some people, certainly for
Roger and myself, it doesn't work for others. No, I'm not saying that
we can carry on conversations underwater.

Cheers,

Christian