Identification of Marine Snails

Identification of Marine Snails

Identification of Marine Snails



Marine snails come in all shapes, sizes, colors, and function, so proper identification is crucial! These marine snails are some of the most frequently available or commonly seen.


Astraea sp (Astrea Snail): Reef Safe

These snails annoy me the most – so much so that I have to question how they aren’t extinct. They frequently tip over and have no ability to right themselves, thus being easy targets for predators. I would avoid this snail unless you have enough time to flip each one back over constantly or enough money to keep buying more.

Cerithium sp. (Cerith Snail): Reef Safe

Cerith snails are a beneficial part of a reef tank clean-up crew. They reproduce in captivity to some extent (some aquarists have more success than others, and juveniles typically make it to adulthood in small numbers). The egg pattern can be very distinctive (depending on species), as shown below. Exact species identification of this marine snail is challenging, as the patterns, shell structure, and anatomy vary so little. Knowing the exact origination region may help.

Collonista Snails: Reef Safe

Most reefkeepers have probably run across the Collonista snail at some point or another – likely as a teeny speck of a snail on live rock or on the glass. These reproduce in captivity faster than the Columbellid snails in my experience, and it isn’t unusual for them to just about cover every surface at night. For whatever reason, I rarely see them grow larger than a pinhead, but I have had some grow over the years to about the size of a pea.

Some hobbyists confuse these as baby Turbo snails or baby Nerites, but they are a separate species. Again, the proper identification of marine snails is important, as these can become a nuisance since small size allows them to clog pumps

Collumbellid Snails (Hawaiian Strombus) (Strombus maculatus): Reef Safe

Ok, so maybe the taxonomy isn’t entirely straightened out on this snail yet, but regardless of name, they’re great snails. As you can see by the egg sacs below, they reproduce faster than rabbits. If you’re sick of buying snails, then these are your best choice, in my opinion. They graze over rocks and on glass, stay small, and their population waxes and wanes with food supply.

Collumbellid Eggs

Strombus sp. (Conch): Reef Safe

If you are looking for a snail with a bit of a personality, then I suggest a conch. They often submerse themselves below the sand with an eyeball or two sticking up to watch their surroundings. They’re great algae-eaters and sand-sifters. I had (what I assume to be) a mated pair that regularly laid eggs. Unfortunately, I never had success raising these in captivity.

Note: Strombus alatus (“Florida Fighting Conch”) and “Tiger Conch” are pictured.

Melongena corona (Crown Conch): Not Reef Safe

Despite the fact that this conch was photographed in front of some zoanthids, this conch is not considered reef safe. They are mollusk predators, and they may even be cannibalistic. Unfortunately, my identification of marine snails as a newbie to the hobby was pretty poor when I bought this conch. Live and learn!

Monetaria annulus (Money Cowrie): Reef Safe

 This fairly small cowrie is reef safe, as it eats a variety of film and hair alga across the tank.

*Note: This cowrie was previously named Cypraea annulus.

Nerita sp. (Nerite Snail): Reef Safe

Nerites are my first choice to purchase. Nerites lay eggs very frequently (small white dots), but unfortunately, I only know of one case personally where a hobbyist was able to get the eggs to grow to adulthood.

The only downside to these snails is that they prefer tidal zones, so they will hang out toward the top of an aquarium. I’ve found quite a few that managed to escape before, and it’s not pleasant. If you need snails to clean your rocks, you may find the Ceriths or Stomatella snails of interest.

Stomatella Snails: Reef Safe

Stomatella snails are one of my favorite hitchhikers. They often come in on live rock or corals, and do well in the home aquarium. But best of all, they reproduce in captivity and will fill an aquarium with babies relatively quickly if there is a lack of predators. Their shell is shaped like a fingernail, which leaves them vulnerable to hermit crabs and other predators (however, they can lose their tail like salamanders can in self-defense). They’re most active at night, and it is not unusual to find them perched on a high rock in the middle of the night releasing what appears to be small puffs of smoke (they’re broadcast spawners.) If you’re looking for an active day-time snail, Ceriths and Nerites are good options.

Black Stomatella Snail

Astraea phoebia (Ninja Star Snail): Reef Safe

I occasionally see these for sale, and of course, I shelled out the extra cash for a “really cool looking snail”. In my opinion, they’re neat, but not worth the extra expense. I am not aware of their reproductive capability in captivity.
Ninja Star

Vermetid Snails: Reef Safe with Caution

Vermetid snails are one of my worst enemies. They are stationary snails as adults and build permanent tube structures on the reef. To catch food, they extend a sticky mucus strand and reel it back in to eat the particles. They aren’t exactly harmful to a reef, but the mucus strands may annoy corals and detract from their physical appearance. And, while they may not be harmful to a reef, they are harmful to soft skin! Picking up a rock with these sharp tubes may cause significant pain/injury and even infection. Use caution when working around these hitchhikers.

Nassarius sp Snails: Reef Safe

Although Nassarius snails are reef safe, there are whelks (predatory snails) that look very similar. Nassarius sp. are great sand-sifters, and they have an amazing sense of smell. Within seconds of adding food to an aquarium they will surface from the sand and head straight for the food.Turbo sp. (Mexican Turbo Snails): Reef Safe

These are the bulldozers of the snail family for a reef aquarium. They grow very large and have voracious appetites to match. Not surprisingly, they are not graceful creatures and will bump rocks and corals over. Beware of these snails if you have an overflow as well. Their shell diameter seems just perfect for clogging plumbing and allowing tanks to overflow. (Yes, it happened to me!)

Many aquarists believe Collonista snails are juvenile turbo snails, but they are a separate species. I have not had success with turbo snail reproduction.

Turbo sp. (Zebra Turbo Snails): Not [Typically] Responsibly Reef Safe

Do you see the Nerite snail to the right of the Zebra Turbo snail? That Nerite is nearly an inch long, for scale. Unfortunately, small Zebra Turbo’s are sometimes sold in the hobby and marketed as great cleaners (which they are!) But, they can become massive bulldozers! This is another example of why proper identification of marine snails is important. These should remain in the wild, or only collected for the absolute largest aquariums. (Sure, there may be some smaller varieties/species than the one shown here, but still, most become bulldozers if they do not starve to death first.)

Scutus antipodes (Elephant Snail): Reef Safe

Although they are generally considered reef safe, as their name implies, there are reports of massively-sized ones in the wild. The ones encountered in the hobby may be a smaller variety. They are members of the limpet family, and they sometimes show a glimpse of their white shell on their back (as shown below).

Zig Zag Periwinkle Snails: Reef Safe

These small snails (about half an inch, maximum), eat algae, diatoms, and detritus throughout the tank. They’re hardy, but I have never had success with their reproduction.

Zig Zag Periwinkles

Dwarf Planaxis Snails: Reef Safe

These are neat reef-safe snails that may even clean in the sand under your rocks. Unfortunately, I’ve never had success with their reproduction.

Pyramidellidae (Pyramidellid Snails): Not Reef Safe

These extremely tiny parasitic snails are shown on the underside of an Astraea snail. Although they typically infest clams in the home aquarium, they also can infest the snail population.

Unfortunately, these came in on a single snail, and then they spread to nearly every snail in the tank. I tried to remove them manually, from every good snail, but I simply couldn’t keep up (or find every single snail every single day). Although I lost all of my snails, the outbreak was contained to my quarantine tank.

I highly recommend lightly scrubbing snail and clam shells, prior to placement in a quarantine tank. So not only is identification of marine snails important, but so is quarantine and observation! The scrubbing can remove adults along with egg masses, and quarantine will allow you time to monitor for any additional adults. However, if some slip by, some wrasse species may help keep the population under control (although, they will probably not eradicate the population since these snails are experts at hiding).

Pyramidellid Snail

Cyphoma gibbosum (Flamingo Tongue Snail): Not Reef Safe

This snail is not commonly encountered in the hobby, for good reason. However, it’s often showcased in scuba-diving photos, which means hobbyists get excited. Unfortunately, it’s a corallivore in cowry family, Ovulidae. Although its spots make it attractive, they are only a part of its mantle.

Margarita Snail: Not [Typically] Responsibly Reef Safe

Last (and least), we have the Margarita (or Margarite) snail. Sadly, these snails are typically taken from colder water, given a tropical-sounding name, and sold as tropical species. They slowly cook internally over a few weeks to months then perish. Please do the responsible thing and discourage import of these colder water species by not purchasing them (unless you have a coldwater tank). If you do purchase these, they may have a better chance of survival in a cooler tank (e.g., 72-78 degrees F).

There are much better choices, especially the captive-reproducing species. Supposedly there are warmer-locale species, and they survive quite well in reef tanks. However, it appears they are rarely imported nowadays (as they’re typically only found in deep waters), and the coldwater species are more common. This is probably the most tragic reason why identification of marine snails is crucial: to only collect suitable and sustainable inhabitants. source

Click to learn more about identification of marine snail eggs!