Damsel fish are one of the hardiest and easiest to keep of all marine fish. They are so durable that people used to use them to cycle new tanks because they could handle the toxic ammonia better then any other fish (I do not recommend or promote using any live animals as a way to start a cycle in your tank....
Algae Scrubber Chronicle: Final Design of the new Algae Scrubber
My Reef Tank and Equipment
Saltwater Aquarium Crabs
37 Gallon Reef: 6/24/2009