Snails play a role in many saltwater aquariums. Marine aquariums, especially reef aquariums, have ideal conditions for algae to thrive and for debris to build up. Various species of snails can help keep up on these issues. However, you need to pick the right snails and get the right number of scavenging snails to avoid complications.
General rules for stocking snails are really guidelines. Every aquarium has important differences that contribute to algae and debris. For example, a powerfully-lit reef tank may have more algae issues than a fish-only aquarium with more subdued lighting. With the limitations of these rules in mind, one or two 4-inch snails per 20 to 30 gallons of aquarium capacity makes a suitable guidelines.
Snails usually need additional food to survive. A healthy aquarium may not provide enough food for algae- and debris-eating snails. Without adequate food, your scavenging snails may pine away and die. You can feed them dried nori, a type of algae. You can get this from pet shops or specialty grocery stores -- sushi chiefs use nori to wrap sushi. Algae wafers, available at pet shops, also make great snail food. Make sure you buy sinking wafers, snails cannot catch floating food.
Picking Your Snails
You also have to pick the right snail for your aquarium. Turbo snails (Turbo spp), also called turban snails, as well as astro snails (Astraea spp.) make great algae-eaters. The cerith snails (Cerithium spp) nassarius snails (Nassarius spp) also help clean aquariums, but general eat debris rather than algae. However, all of these families also include temperate species that sometimes find their way into pet shops. These snails tend to die off in tropical aquariums. Always buy your snails from a reputable dealer to make sure you have tropical species.
Many reef aquariums feature groups of invertebrates called cleanup crews. Aquarium hobbyists often abbreviate them CUCs. CUCs typically include snails, shrimps, brittlestars and crabs that complement each other by eating different types of algae or debris. However, some less-than-scrupulous dealers will throw together a random grab-bag of invertebrates and sell them as CUCs. These "CUCs" may include coral-eating inverts like arrow crabs. Always purchase your CUCs from reputable dealers.
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