Saltwater Snails - there are a variety of snails and a variety of things they like to eat.
And snails eat more than just algae!!
We will focus this conversation to the common saltwater aquarium snails and what they eat.
There are 2 main eaters - Algae Eaters and [ame="http://en.wikipedia.org/wiki/Detritus"]Detritus - Wikipedia, the free encyclopedia[/ame] Eaters.
The most common Algae eaters are Turbos, Astreas, Mexican Turbos, Ceriths and Nerites. These snails hail from Caribbean waters and are great for the warmer temperatures of the normal saltwater aquarium. Other warm water algae eaters are Extra Large Cerith Snails, Stocky Cerith Snails & Tapestry Snails.
Algae Eating Snails are recommended at ~30% of the tank volume. So if your tank is 100 gallons - you would want to add 30 algae eating snails - that is a combination of all types - since it is advisable to have a variety of algae eaters in your tank.
Detritus Eating Snails are a real blessing - they eat the YUCK that causes nitrates which feed the algae. So if you want less algae you MUST reduce the nitrates first. Nassarius Vibex are the Queen Gems - they can be kept at 1-2 snails per gallon. They eat left over food, dead stuff, waste from other animals - lots of yucky stuff- NATURALLY!
Right now at Reefs2go.com - our snails are all on sale - so get 'em cleaning for you.