Hello,
I am working on a little something for my blog (aquariumslife.com). Its about snails for the reef aquarium. There is still some missing things and I would love to make sure the information I have is exact.

Here is what I have:

Turbo Snails - Turbo sp
Distribution: Gulf of California off the coast of Mexico
Water condition: 72-78° F, dKH 8-12, sg 1.023-1.025, pH 8.4-8.4
Active time: Day
Size: 3 in.
Diet: Herbivore
Zone: They will go over every inch of your aquarium
Pros: Excellent against green hair algae.
Cons: Will bulldoze loose rocks in search for food so make sure rocks are well-secured. They cannot right themselves if they fall and land on their back. You will have to right it to prevent its demise.

Tip: If you have some type of rubble in your sandbed, Turbo snails can manage to right themselves.

Astraea Snails - Astraea tectra, Astraea phoebia
Distribution: Caribbean
Water condition: 72-78° F, dKH 8-12, sg 1.023-1.025, pH 8.1-8.4
Active time: Day
Size: 1 in.
Diet: Herbivore
Zone: All
Pros: Excellent against cyanobacteria, green and brown film algae (maybe not green hair algae). Should not nock over corals and loose rocks (They do in my tank)
Cons: They cannot right themselves if they fall and land on their back. You will have to right it to prevent its demise.

Tip: If you have some type of rubble in your sandbed, Astraea snails can manage to right themselves.

Trochus or Turban Snails - Trochus sp.
Distribution: Indo-Pacific
Water condition: 72-78ºF; sg 1.023-1.025; pH 8.1-8.4
Active time:
Size: 1 inch
Diet: Herbivorous
Zone: All (including glass)
Pros: Excellent against green hair algae, slime algae, green algae, cyanobacteria and diatoms. They leave nothing behind. They are able to right themselves if they fall on their backs.
Cons:

Nerite Snails - Nerita and Neritina
Distribution: Caribbean, Pacific Ocean
Water condition: 72-78°F; sg 1.020-1.025; pH 8.1-8.4; dKH 8-12
Active time:
Size: 1 in.
Diet: Herbivorous
Zone: Rocks and Glass
Pros: Excellent against cyanobacteria, green algae and are just great to remove algae film on glass. They are able to right themselves if they fall on their backs. Do not disturb the landscaping.
Cons: Commonly reported to escapes from tanks.

Stomatella Snails (Stomatella varia)
Distribution: Western Central Pacific: Indonesia, Philippines and Guam
Water condition: 72-78ºF; sg 1.023-1.025; pH 8.1-8.4
Active time: Day and Night (mostly night)
Size: 3/4 inch.
Diet: Herbivorous
Zone: live rock, will clean the glass
Pros: They are herbivores and feed upon micro algae in the reef tank. They are to small to ever knock corals over. Reproduction is easy: more food = more snails
Cons: Sometime considered as a nuisance because of its rapid reproduction. Peppermint shrimp are known to eat this snail.

Bumble Bee Snails - Engina mendicaria, Pusiostoma sp
Distribution: Marshall Islands
Water condition: 72-78° F, dKH 8-12, sg 1.023-1.025, pH 8.1-8.4
Active time:
Size: 1/2 in.
Diet: Carnivore, Detritus.
Zone:
Pros:
Cons: Lack any ability to feed from algae although they are commonly sold as good algae eater. Feed on sand bed fauna and have been reported to prey on other snails.

Margarita Snails - Margarites sp.
Distribution: Eastern Pacific region, the Caribbean Sea including Alaska and Baja California.
Water condition: 50-68° F, dKH 8-12, sg 1.023-1.025, pH 8.0-8.4
Active time: Night
Size: 1 in
Diet: Herbivore
Zone: rocks, sand
Pros: Good against green hair algae, Cyanobacteria and diatoms
Cons: Do not survive in a typical reef system kept at 80F.

Super Tongan Nassarius - Nassarius distortus
Distribution: Tonga
Water condition: 72-78°F; sg 1.023-1.025; pH 8.1-8.4; dKH 8-12
Active time: Day
Size: 1 in.
Diet: Omnivore
Zone: Sand
Pros: Excellent to remove detritus from the sandbed. Will keep the sandbed stirred and oxygenated. Will not nock over corals and loose rocks. A must with deep sandbed.
Cons:

Nassarius Snails - nassarius vibex
Distribution: Caribbean
Water condition: 72-78° F, dKH 8-12, sg 1.023-1.025, pH 8.1-8.4
Active time: Day
Size: 1/2 in.
Diet: scavenger
Zone: Sand
Pros: Excellent to remove detritus from the sandbed. Will keep the sandbed stirred and oxygenated. Will not nock over corals and loose rocks. A must with deep sandbed.
Cons:

Keyhole Limpet snails - Megathura crenulata
Distribution: Eastern Pacific
Water condition: 72-78ºF; sg 1.023-1.025; pH 8.1-8.4
Active time:
Size: 3 in.
Diet:
Zone:
Pros: They are great for eating hydroids and will also feed upon all forms of microalgae.
Cons: They have been known to sometimes graze on Acropora, Montipora and other similar species.

Cerith Snails - Cerithium sp.
Distribution: Mostly found in Caribbean
Water condition: 72-78° F, dKH 8-12, sg 1.023-1.025, pH 8.1-8.4
Active time: night
Size: less than 1½ in.
Diet: Omnivore
Zone: Sand
Pros: Very active eaters. Excellent to remove detritus from the sandbed. Will keep the sandbed stirred and oxygenated. Excellent against brown diatoms and slime algae that grow on the sand. One of the only snails that will eat algae that grow below the sand near the front of your aquarium. Do not bother invertebrates.
Cons:

Red Footed Conch or Thorn Latirus - Opeatostoma pseudodon
Distribution: Nicaragua
Water condition: 72-78° F, dKH 8-12, sg 1.023-1.025, pH 8.1-8.4
Active time:
Size:
Diet: Omnivore
Zone:
Pros: Will eat both algae and detritus.
Cons:

Florida Fighting Conch - Strombus Alatus
Distribution:
Water condition: 72-78° F, dKH 8-12, sg 1.023-1.025, pH 8.1-8.4
Active time: Night
Size: 1 in.
Diet: Omnivore
Zone: Sand
Pros: Excellent to remove detritus from the sandbed. Will keep the sandbed stirred and oxygenated. Excellent against brown diatoms and slime algae that grow on the sand. Do not bother invertebrates.
Cons: They have been reported to hunt other snails.

Abalone - Haliotis sp
Distribution:
Water condition: 64-75ºF; sg 1.023-1.025; pH 8.1-8.4
Active time: Night
Size:
Diet: Herbivore
Zone:
Pros: Some say it is the best herbivore for the reef aquarium.
Cons: They may become somewhat of a nuisance, as they can clog pumps and monitor impellers. They prefer a cooler aquarium.

Tiger Cowrie
Distribution: Indo-Pacific
Water condition: 72-78ºF; sg 1.023-1.025; pH 8.1-8.4
Active time:
Size: 4 in.
Diet: Omnivore
Zone:
Pros:
Cons: Mature specimens has been reported to eat anemones, soft corals and tube worms.

Chestnut Cowrie - Cypraea tigris
Distribution: Indo-Pacific
Water condition: 72-78ºF; sg 1.023-1.025; pH 8.1-8.4
Active time: Day
Size: 4 in
Diet: Carnivore
Zone:
Pros: Great algae and detritus eater.
Cons: Mature specimes will eat soft coral and sponges.

Stomatella
Distribution:
Water condition:
Active time:
Size:
Diet:
Zone:
Pros: Known to eat algae.
Cons:

Dwarf Sea Hare - Aplysia sp
Distribution: Nicaragua
Water condition: 72-78° F, dKH 8-12, sg 1.023-1.025, pH 8.1-8.4
Active time:
Size: 1 in.
Diet: Herbivore
Zone:
Pros: Will graze on algae and eat any Caulerpa (a macroalgae species).
Cons: Difficult to keep. Release a purple toxic dye to repel attacking fish. A good chemical is needed to quickly remove this toxic dye.

Ill look into some of these over the holiday weekend but right off the bat the temps look low for the regions some of these come from and the SG range is lower then NSW

Right, the listed temps and salinities are almost all too low. The salinities for all of them should be 1.025 or higher. For the tropical species, the temp range is 76-86. However, several of the species listed aren't tropical.

Turbo fluctuosus, which is the common species from Mexico and the Gulf of California, isn't tropical. They're collected in the same areas as margarita snails. Sometimes Turbo castaneaus, which is from the east coast is also available and the info is about the same. The "zebra Turbo" are actually Cittarium pica which are more closely related to Trochus than Turbo. They're from the Caribbean and are one of the few tropicals offered in the hobby. They grow to 6 inches though.

Astraea are Astraea or Lithopoma tecta, not "tectra," and Astralium phoebium.

Trochus are active day and night.

Nerites are active by night. They're intertidal, so most will hang out near the top of the tank and some will even crawl out.

Bumblebee snails will cruise the rocks and sand, but usually like to stay close to the rockwork.

Margarita snails are Tegula, not Margarites. There are species distributed in most of the areas you listed, but the ones in the hobby are mostly from the Baja California. Like you said, they're not tropical.

Nassarius vibex feeds on carrion which is dead animal material and uneaten food. They don't feed on detritus, which is poop and rotting plant material. It's an important distinction since there's usually a lot less of the former than the latter.

There are dozens of different keyhole limpets that show up in the hobby from all over the world- M. crenulata isn't likely to be one of them. Diodora is probably the most common genus. Almost all are nocturnal omnivores. The species that show up in the hobby range in size from a few mm to 3 inches. Most like rocks, but will sometimes congregate at the sand line on the glass and they will clean below the sand line.

Ceriths are mostly Cerithium or close relatives, but they're not just tropical species coming from the Caribbean. A large portion of them are subtropical species from Baja California like many of the Turbo and margarita snails. Sometimes these are sold as Baja ceriths, but not always.

There are several unrelated snails sold as red footed conchs. All of them, including O. pseudodon are primarily carnivorous, specializing in mollusks and sometimes crustaceans. There's little or no algae in their diets. O. pseudodon comes from the Pacific coast of Central America and Mexico and grows to about 4 inches. They prefer rocks.

Fighting conchs feed only on algae and detritus, so really can't be considered omnivores. They also grow to about 6 inches. They NEVER hunt other snails. They don't have the anatomy for it. These reports are almost always due to misidentification, usually either Melongena corona or other whelks with "conch" in the common name. True conchs have well developed eyes with irises and pupils that distinguish them from other similar snails.

There are tropical abalone that are well suited to reef temperatures. However, there are also coldwater or temperate species. Neither is common in the hobby though so it's hard to say which someone is more likely to come across in the store. Abalone are found on rocks. They range in size from 3-10 inches depending on species. Most of the tropical species are at the lower end.

Tiger cowries prefer sand at the base of rocks and are active mostly at night. Chestnut cowries tend to prefer more rock.

Dwarf sea hares are usually Dolabrifera brazieri, not Aplysia and they can be found throughout the Caribbean. The larger seahares are usually Dolabella auricularia, which comes from the Indo-Pacific and can grow to almost a foot. Most species of Aplysia get very large and fortunately, very few of them show up in the hobby and only infrequently. They can be found almost worldwide. The blue spotted sea hare Bursatella leachii, which is from the SE US and the Caribbean are collected seasonally when they gather in the shallows to breed (and then die shortly afterward). They feed on diatoms and cyano and grow to about 6 inches. However, most in the hobby will not last long since they're collected near the end of their lifecycle. Not all of these species produce ink, but in any event, sea hare ink is not toxic. It's just a soup of amino acids that overwhelms the senses of predators. With the exception of Dolabrifera, these are almost all lagoonal animals that tend to prefer the sand, though they will go onto the rocks, and they don't handle high flow very well. They're mostly active at night.

Aplysia spp. feed almost exclusively on red algae like Graciliaria sp. Although they will eat other kinds of algae, they can't sustain themselves on it (they need the macro stuff). Sea slugs are also very short lived animals and it will most likely die in your tank within a few months. Obviously, they bigger the slug, the more they will foul your water when they die.

Thank you for that review! It's to bad I can't edit the first message. I would have prefer to edit the first one to make sure no one use some wrong info.
I tried to add everything you said in this. I hope I did it right. I was unsure about Blue Spotted Sea Hare and Dwarf Sea Hare. I hope it's like they should be now.

I realize how confusing this can be. Most of those genus include many species and the information we find about each often mix the information from from many species.


Turbo Snails - Turbo sp
Distribution: Gulf of California off the coast of Mexico
Water condition: 72-78° F, dKH 8-12, sg 1.025, pH 8.4-8.4
Active time: Day
Size: 3 in.
Diet: Herbivore
Zone: They will go over every inch of your aquarium
Pros: Excellent against green hair algae.
Cons: Will bulldoze loose rocks in search for food so make sure rocks are well-secured. They cannot right themselves if they fall and land on their back. You will have to right it to prevent its demise.

Tip: If you have some type of rubble in your sandbed, Turbo snails can manage to right themselves.

Astraea Snails - Astraea tecta, Astraea phoebium
Distribution: Caribbean
Water condition: 72-78° F, dKH 8-12, sg 1.025, pH 8.1-8.4
Active time: Day
Size: 1 in.
Diet: Herbivore
Zone: All
Pros: Excellent against cyanobacteria, green and brown film algae (maybe not green hair algae). Should not nock over corals and loose rocks (They do in my tank)
Cons: They cannot right themselves if they fall and land on their back. You will have to right it to prevent its demise.

Tip: If you have some type of rubble in your sandbed, Astraea snails can manage to right themselves.

Trochus or Turban Snails - Trochus sp.
Distribution: Indo-Pacific
Water condition: 72-78ºF; sg 1.025; pH 8.1-8.4
Active time: Day and Night
Size: 1 inch
Diet: Herbivorous
Zone: All (including glass)
Pros: Excellent against green hair algae, slime algae, green algae, cyanobacteria and diatoms. They leave nothing behind. They are able to right themselves if they fall on their backs.
Cons:

Nerite Snails - Nerita and Neritina
Distribution: Caribbean, Pacific Ocean
Water condition: 72-78°F; sg 1.025; pH 8.1-8.4; dKH 8-12
Active time: Night
Size: 1 in.
Diet: Herbivorous
Zone: Rocks and Glass
Pros: Excellent against cyanobacteria, green algae and are just great to remove algae film on glass. They are able to right themselves if they fall on their backs. Do not disturb the landscaping.
Cons: They are intertidal, so most will hang out near the top of the tank and some will even escapes from tanks.

Stomatella Snails (Stomatella varia)
Distribution: Western Central Pacific: Indonesia, Philippines and Guam
Water condition: 72-78ºF; sg 1.025; pH 8.1-8.4
Active time: Day and Night (mostly night)
Size: 3/4 inch.
Diet: Herbivorous
Zone: live rock, will clean the glass
Pros: They are herbivores and feed upon micro algae in the reef tank. They are to small to ever knock corals over. Reproduction is easy: more food = more snails
Cons: Sometime considered as a nuisance because of its rapid reproduction. Peppermint shrimp are known to eat this snail.

Bumble Bee Snails - Engina mendicaria, Pusiostoma sp
Distribution: Marshall Islands
Water condition: 72-78° F, dKH 8-12, sg 1.025, pH 8.1-8.4
Active time:
Size: 1/2 in.
Diet: Carnivore, Detritus.
Zone: Sand and rock but usually like to stay close to the rockwork.
Pros:
Cons: Lack any ability to feed from algae although they are commonly sold as good algae eater. Feed on sand bed fauna and have been reported to prey on other snails.

Margarita Snails - Tegula sp.
Distribution: Mostly collected in the Baja California
Water condition: 50-68° F, dKH 8-12, sg 1.025, pH 8.0-8.4
Active time: Night
Size: 1 in
Diet: Herbivore
Zone: rocks, sand
Pros: Good against green hair algae, Cyanobacteria and diatoms
Cons: Do not survive in a typical reef system kept at 80F.

Super Tongan Nassarius - Nassarius distortus
Distribution: Tonga
Water condition: 72-78°F; sg 1.025; pH 8.1-8.4; dKH 8-12
Active time: Day
Size: 1 in.
Diet: Omnivore
Zone: Sand
Pros: Excellent to remove detritus from the sandbed. Will keep the sandbed stirred and oxygenated. Will not nock over corals and loose rocks. A must with deep sandbed.
Cons:

Nassarius Snails - nassarius vibex
Distribution: Caribbean
Water condition: 72-78° F, dKH 8-12, sg 1.025, pH 8.1-8.4
Active time: Day
Size: 1/2 in.
Diet: scavenger. Feeds on dead animal material and uneaten food. Not on detritus (poop and rotting plant material)
Zone: Sand
Pros: Excellent to remove detritus from the sandbed. Will keep the sandbed stirred and oxygenated. Will not nock over corals and loose rocks. A must with deep sandbed.
Cons:

Keyhole Limpet snails - Diodora is the most common
Distribution: Most are from Baja California
Water condition: 72-78ºF; sg 1.025; pH 8.1-8.4
Active time: Nocturnal
Size: up to 3 in.
Diet: Herbivore
Zone: Most like rocks, but will sometimes congregate at the sand line on the glass and they will clean below the sand line.
Pros: They are great for eating hydroids and will also feed upon all forms of microalgae.
Cons: They have been known to sometimes graze on Acropora, Montipora and other similar species.

Note: There are dozens of different keyhole limpets in the hobby. They come from all over the world but Diodora is probably the most common genus. Thy range from a few mm to 3 inches in size.


Cerith Snails - Cerithium sp.
Distribution: Mostly found in Caribbean
Water condition: 72-78° F, dKH 8-12, sg 1.025, pH 8.1-8.4
Active time: night
Size: less than 1½ in.
Diet: Omnivore
Zone: Sand
Pros: Very active eaters. Excellent to remove detritus from the sandbed. Will keep the sandbed stirred and oxygenated. Excellent against brown diatoms and slime algae that grow on the sand. One of the only snails that will eat algae that grow below the sand near the front of your aquarium. Do not bother invertebrates.
Cons:

Red Footed Conch or Thorn Latirus - Opeatostoma pseudodon
Distribution: Pacific coast of Central America and Mexico
Water condition: 72-78° F, dKH 8-12, sg 1.025, pH 8.1-8.4
Active time:
Size: 4 in.
Diet: Primarily carnivorous, specializing in mollusks and sometimes crustaceans. There's little or no algae in their diets.
Zone: They prefer rocks.
Pros:
Cons: Will feed on mollusks and sometimes crustaceans.

Florida Fighting Conch - Strombus Alatus
Distribution:
Water condition: 72-78° F, dKH 8-12, sg 1.025, pH 8.1-8.4
Active time: Night
Size: 6 in.
Diet: Algae and detritus
Zone: Sand
Pros: Excellent to remove detritus from the sandbed. Will keep the sandbed stirred and oxygenated. Excellent against brown diatoms and slime algae that grow on the sand. Do not bother invertebrates.
Cons:
Note: They NEVER hunt other snails. They don't have the anatomy for it. These reports about snails hunting are almost always due to misidentification, usually either Melongena corona or other whelks with "conch" in the common name. True conchs have well developed eyes with irises and pupils that distinguish them from other similar snails.


Abalone - Haliotis sp
Distribution:
Water condition: sg 1.025; pH 8.1-8.4
Active time: Night
Size: 3 to 10 inches depending on species. Most of the tropical species are at the lower end.
Diet: Herbivore
Zone: Rocks
Pros: Some say it is the best herbivore for the reef aquarium.
Cons: They may become somewhat of a nuisance, as they can clog pumps and monitor impellers. They prefer a cooler aquarium.
Note: Abalone that are well suited to reef temperatures. However, there are also coldwater or temperate species.

Tiger Cowrie
Distribution: Indo-Pacific
Water condition: 72-78ºF; sg 1.025; pH 8.1-8.4
Active time: Mostly at night.
Size: 4 in.
Diet: Omnivore
Zone: Prefer sand at the base of rocks
Pros:
Cons: Mature specimens has been reported to eat anemones, soft corals and tube worms.

Chestnut Cowrie - Cypraea tigris
Distribution: Indo-Pacific
Water condition: 72-78ºF; sg 1.025; pH 8.1-8.4
Active time: Day
Size: 4 in
Diet: Carnivore
Zone: Rocks
Pros: Great algae and detritus eater.
Cons: Mature specimes will eat soft coral and sponges.

Stomatella
Distribution:
Water condition: 72-78° F, dKH 8-12, sg 1.025, pH 8.1-8.4
Active time:
Size:
Diet:
Zone:
Pros: Known to eat algae.
Cons:

Dwarf Sea Hare - usually Dolabrifera brazieri
Distribution: Caribbean
Water condition: 72-78° F, dKH 8-12, sg 1.025, pH 8.1-8.4
Active time: Night
Size: 1 in.
Diet: Herbivore
Zone: Prefer the sand, though they will go onto the rocks
Pros: Will graze on algae and eat any Caulerpa (a macroalgae species).
Cons: Difficult to keep. Release a purple toxic dye to repel attacking fish. A good chemical is needed to quickly remove this toxic dye.

Blue Spotted Sea Hare - Bursatella leachii
Distribution: South-East USA and Caribbean
Water condition: 72-78° F, dKH 8-12, sg 1.025, pH 8.1-8.4
Active time: Night
Size: 6 in.
Diet: Herbivore. Feed on diatoms and cyano
Zone: Prefer the sand, though they will go onto the rocks.
Pros: Will graze on diatoms and cyano.
Cons: Most will not last long since they are collected when they gather in the shallows to breed, just before the end of their lifecycle. They don't handle high flow very well.
Note: The purple dye they repel is not toxic.

Hi patrice

I keep Trochus snails and have never had a problem with them at all.They never bother my corals nor anything else, they do an ok job on my algae. "would like it to be better ,but they are the best in my opinion."

Cheers