Aquatic snails may be the least appreciated animals available to tropical fish enthusiasts, and many people simply classify most snails as scavengers—or just pests. In fact, there are many highly desirable snails out there, some quite beautiful and fascinating to watch, and new species are regularly imported. This guide is meant to help distinguish the snails you may want from those that are best avoided.
The apple snail is a successful model of nature: it has existed in its present form for more than 150 million years. Apple snails have been around since the days of the dinosaurs and have been kept by generations of aquarium keepers. They are undemanding and relatively resilient.
Ideal for aquariums is the SPIKE-TOPPED APPLE SNAIL, Pomacea diffusa. They eat no living plants, but consume food leftovers and other organic material, and thus make a major contribution to the cleanliness of the aquarium. The variety of available color morphs contributes to their popularity. A white or blue-black body color can be combined with yellow, brown, purple, pink, or white shells. The shells of these animals average 1.6-1.8 inches (40-45 mm) in size. They lay their eggs outside the water in calcareous cocoons that contain 100-250 eggs and, with a size of 1-2 inches (2.5-5 cm), are easy to find. They can be removed easily when no offspring are desired.
The ZEBRA APPLE SNAIL, Asolene spixi, has a white to gray, brown-speckled body and a yellow shell with brown or black lines. They feed mainly on uneaten food. They may partially eat the shoots and leaves of soft plants, but in a densely planted aquarium this is barely noticeable. They lay gelatinous egg casings containing 10 to 30 eggs underwater on plants or decorations. After about 14days the eggs hatch. As long as the population is not too large, these snails do not cause significant damage.
Other apple snails, such the Channeled or Golden Apple Snail, Pomacea canaliculata, the Apple Snail, P. glauca, and Marisa cornuarietis, all eat plants, including Anubias, Java Fern, and Cryptocoryne, so they are not suitable for planted aquariums. However, the animals are easy to maintain and are kept by many snail fans. Apple snails live to be about two years old.
Snails of the family Thiaridae are, in principle, all suitable for the aquarium. Melanoides tubercular, the MALAYSIAN (OR MALAYAN) TRUMPET SNAIL (often abbreviated to MTS, aka the Malayan livebearing snail), is considered the “earthworm of the aquarium.” These animals are all female and reproduce via unfertilized eggs, which they keep in a brood pouch behind their heads until the young hatch and are released into the water. The proliferation rate is very high and with a good supply of food, the animals multiply en masse. In the aquarium, the shells rarely get longer than 0.4-0.6 inch (1-1.5 cm). In nature, these animals reach a shell length of 2.4 inches (6 cm) or more.
The PAGODA TIARA, Thiara scabra, has a 0.6 inch (1.5 cm) shell with bulbous turns and nodes and thorns on the ridges. These animals also reproduce by parthenogenesis and bear live young. But they proliferate more slowly than Melanoides tuberculata and cannot compete with them. Therefore, you should not mix these species.
Typical for the large HAIRY TRUMPET SNAIL, Thiara cancellata (up to 1.2 inches/3 cm), are the stiff, rear-facing bristles. The animals look interesting and are long-lived in aquariums. They produce free-floating larvae, which, unfortunately, have not yet been successfully reared in the aquarium.
We maintain the genera Tylomelania, Brotia, and Faunus from the family Pachychilidae in our aquariums. With Brotia and Tylomelania the mortality of newly acquired animals is very high. Their chances of survival seem to depend on how different the water parameters are during transport, holding, and in the aquarium compared to those in their original locality. Captive breeding successes are still very infrequent with these species. Although these viviparous snails often release babies shortly after their arrival, the young rarely survive. Apparently, sexual maturity doesn’t begin until the age of one to one and a half years, or even later—and both males and females are needed for breeding.
So far, I have only been able to maintain some GOLDEN SPOTTED RABBIT SNAILS, Tylomelania towutensis, and one GIANT TOWER CAP SNAIL, Brotia herculea, over a longer period of time. However, there were no Tylomelania babies for over three years. All other Brotia and Tylomelania species died within three weeks of purchase. They are not very suitable for a community aquarium; they do not like disturbances or competition from other snails or fishes. A species tank is the best way to keep these animals.Aquarists using special salts with Tylomelania, such as those sold for Sulawesi shrimp, report varying results. Some specimens that had been doing well in regular tap water died after the addition of these salts. Other animals did well in the treated water, together with shrimps from the region. Themain factor with so-called Sulawesi snails seems to be whether the snails were collected in lakes or in the Indonesian river tributaries. Unfortunately, information on their original habitat is hard to come by when purchasing these snails.
Less demanding is the BLACK FAUNUS, Faunus ater. This snail is very long-lasting and robust. The smooth, dark brown to black shell can be over 3 inches (8 cm) long. Since these snails release free-floating larvae, they do not multiply in the aquarium.
Neritidae—Nerites & Fruit Snails
Nerites and “Fruit Snails” belong to the family Neritidae. They eat stubborn green algae and diatoms by cracking the sometimes very hard algal cells growing on the substrate and digesting their contents. The TURRETED NERITE, Neritina turrita, the BASEBALL HELMET NERITE, N. pul-ligera, and the HORNED NERITE, Clithon diadema, are very durable aquarium snails. They effectively consume algae but also take uneaten food. Unfortunately, they cannot reproduce in the aquarium because the tiny planktonic larvae that hatch from their showy white egg cocoons require salt water to mature.
The aquarium should be well covered, because most of these animals leave the water from time to time and are liable to fall off the edge of the aquarium. Although they can survive for some time out of the water, they should not be on dry land for too long. The life expectancy for nerites is 10-15 years.
Septaria and some Clithon species have a very high mortality rate. They come in part from brackish water, or refuse substitute food and starve in the aquarium. Therefore, they are not recommended for the hobby.
New species from the family Viviparidae are introduced into the aquarium trade regularly, but most do not last long. However, a very good aquarium snail is the NUBBY PIANO SNAIL, Taia naticoides. Sexually mature specimens have a light brown to dark brown striped housing with fine nodules. The shells of young snails are smooth.The animals reproduce quite well in the aquarium and can handle competition from other snails.
The THAI TIGER SNAIL, Filopaludina sumatrensis, has not been kept in captivity with lasting success. Although the adult snails release juveniles, they usually die within a few days, and even the adult animals rarely survive longer than four weeks in the aquarium.
Completely unsuitable for the aquarium is the BLUE TURBO SNAIL, Celetaia persculpta, from Lake Poso, Sulawesi. The animals do not adjust to normal freshwater aquariums—even in tanks in which the conditions of the natural habitat were replicated, these animals lasted a few weeks at most.
POND, RAMSHORN, and BLADDER SNAILS are often perceived as pests or threats to plants. In fact, they are ideal aquarium animals. With the exception of pond snails (Lymnaeidae) with shells larger than 0.4 inch (1 cm), they do not harm plants, but eat only dead and diseased plant tissue, algae, uneaten food, and dead animals. Dot-shaped holes in the plant leaves are caused when the snails feed on the dead tissue caused by potassium deficiency. Only very large pond snails eat living plant tissue.
These snails become sexually mature within a few weeks. They are hermaphroditic and lay many eggs in a short time, breathe atmospheric oxygen, and cope well with polluted water. Their numbers depend on how much excess feed gets into the aquarium. If you don’t want to reduce the amount of food because some fishes might not get enough, you can dispense the food over several feedings so they can consume everything quickly. Snails only eat what is left over. As a result, they keep the tank clean, reduce the risk of microbial blooms, and combat the proliferation of blue-green algae. In a snail tank, there are usually no algae problems.