Here is a list of snails that are unsuitable for most reef aquariums:
- Flamingo Tongue - A beautiful snail that feeds solely on gorgonians.
- Murex Snails - All of the snails in this family are predatory, and will feed on herbivorous snails, leaving your tank with algae.
- Ilynassa Obsoleta - a big seller on Ebay, as their colonies blanket the coasts of temperate shores. They are a colder water snail that scavenges and eats other snails and bivalves and is not suitable for reef aquariums
- Margarita Snails - this very popular snail's range does not extend into the tropics, and they will be stressed in normal reef tanks, because they are not built to tolerate reef temperatures. A good snail though if your tank rarely goes to 70 degrees, they are excellent algae cleaners in a temperate tank, and a favorite among many hobbyists with cold water biotopes.
- Crown Conchs - A predatory snail that will eat other herbivorous snails, leaving your tank with algae. They are also cannibalistic and not related to true Conchs, it is a name given to them by dry shell collectors because their shell is similar in shape to true Conchs which are herbivores.
- Queen Conchs - these herbivorous snails are great at first, but when they become close to 12 inches long, 4 inches tall, and 5 inches wide, they are just too big for most tanks, as they need a large amount of area to survive. At that size they also bulldoze most rock formations.
- Keyhole Limpets - Not all limpets are the same. Owning a limpet is like owning a snail, the species really matters. Many of the keyhole limpets are known predators, some of which feast on SPS coral. If you keep coral, only keep species limpets who are herbivorous. Not all keyhole limpets are predatory, but you should be wary when adding them to a tank without prior knowledge of their diet.
- Olive Snails - These snails have been popping up in the hobby, and it is a shame. They are predatory, and feed on small bivalves, microfauna and other snails. They also scavenge, but they are opportunistic.
Snails you should know about -
- Commercial Trochus - (Trochus niloticus) this species of Trochus snail grows very large, about 4.5 inches in diameter and the same height. As an adult, it is only suitable for very large aquariums with very large corals or stable rock structures otherwise it can be a bulldozer.
- Zebra Turbos - (Cittratum picta) grows even bigger, at 5 inches in diameter, it is sold as the Zebra Turbo in the hobby. It is an excellent cleaner, but will become a bulldozer in all but the largest aquariums with very stable structures.
- Bumble Bee Snail - Sold as a sand stirrer, that will scavenge and prey on vermetid worms, it also eats the micro fauna in your sand that makes it "live". The extent of the damage this can cause is uncertain, and most aquarists do not notice the impact.
- Babylonian Snails - This cream and brown spotted snail makes an attractive addition to the tank, but may feed on microfauna and sessile inverts. They are often mislabeled and sold as "Tiger Nassarius", or "Speckled Nassarius" snails, but they are not related to Nassarius spp.