Good post GaryP!

Thunderkat and demodiki: Regarding the husbandry of rays
"If an undergravel filter is not used, the depth of subtrate material should be kept to a minimum (5cm [about 2in] or less). This is especially true for very fine sand, which can readily become anaerobic."

"The larger grades of crushed coral and dolomite can irritate the animal's ventral surface and cause bacterial infections."

-Aquarium Sharks and Rays: The Essential Guide to Their Selection, Keeping, and Natural History by Scott W. Michael (pg 52-53)

Sharks and rays ARE vastly different than the bony fish we keep...even their gills and skin omit ammonia (bony's do to...but sharks and rays are a lot larger so have more of an impact). They really do require a special tank and wont thrive in a 'regular' reef tank. Not to say that reefkeeping techniques should not be used...b/c they should, their are just different issues and problems that need to be addressed.

As a side note angels ARE NOTORIOUS for picking at elasmobranch's (sharks and rays), repeatedly biting them which may cause and infection and kill the animal.

Compboy: What type of ray?