While on Maui this last week, we've spent quite a bit of time snorkeling at one of my favorite spots on the whole planet, Ulua Beach. Most days, we've brought a small bag of frozen peas to feed the fish. As soon as you get out over the reef, the Unicornfish all recognize the bag and swarm over to you hoping for a treat. If they could make noise, they'd all be crying for noms like our Maximum Leader does when she smells an open can of tuna.
The Unicornfish were at the top strata of the water and always managed to get the peas first, but with a sufficiently large spray of them, plenty of peas would make it down to the Triggerfish and others in the middle strata. At one spot, down on the bottom was a huge Ornate Wrasse (I think that's what it was) that should have had a little light on it's head and been making vacuum cleaner sounds as it sucked up all the peas that fell to it.
Before we left on this trip, I considered getting an underwater camera or a waterproof case for the ones we had. The cameras were a bit too expensive and the cases came with sufficient user reviews claiming leakage and camera destruction to prevent me from buying them. Maybe next time.