with apple snails
by Stijn Ghesquiere



While keeping the information on this website as objective as possible, I thought it would be nice to tell about my own personal experiences with certain apple snail species. So keep in mind that the information within this page is -not- based on scientific articles, but a reflection of the author's opinions and experiences. If you do not agree with things described on this page, or on the opposite: you have had similar experiences, I'll be glad if you let me know (click here).


Pomacea diffusa

Pomacea bridgesi
Shell of a dark wild-form Pomacea diffusa (bridgesii) snail.

Pomacea bridgesi
Shell of a dark wild-form Pomacea diffusa (bridgesii) snail, back view.
Pomacea bridgesi
Pomacea diffusa
yellow (golden) variant.
Note the flat top of the whorls.

Pomacea diffusa is the apple snail I started with when I bought 2 yellow snails in the fall of 1997. At that time I had no idea what and how about apple snails. I even wasn't aware that I bought a pigment lacking variety of this apple snail (the natural form is almost black).
Anyway, these snails are relatively easy to keep in captivity. They do not eat aquarium plants and hardly eat any lettuce. To keep them healthy I feed them fish food and sometimes a slice of cucumber. They produce eggs all year round with a peak in spring (March-April) and a winter stop (October-December). The eggs are closely attached to each other and the little snails appear after 2-3 weeks, although it can take even 3-4 weeks at lower temperatures. Once the little snails arrive, the difficulty with this snail species comes clear: the first weeks are hard for them. At least in my case. But after a while I noticed that the best way to raise these snails is by keeping the young in the same tank as the parents. It also helps to -not- clean the tank too well. Apparently the baby diffusa snails eat waste from the tank sides.
Temperature is not a hot topic with my Pomacea diffusa (bridgesii) snails as long as I keep the temperature above 18°C. They become completely inactive at lower temperatures and eventually die if the temperature is maintained low.
Pomacea diffusa snails can at least live for about 2-3 years and maybe older. I noticed vanishing of their smooth shell surface when they grow older. Snails that are over 1 year gradually loose the surface layer of their shell, which results in a colour loss as the colourless calcium layers of the shell become visible. Also, these snails become less active over time and their tentacles and foot becomes a bit swollen. It appears to me that these snails get problems with their osmotic regulation when they get old, which results in a fluid excess in the tissues.
My Pomacea diffusa snails are not very active during the day (the adults always reside on the bottom, while the juveniles mostly reside near the water surface). Their activity levels drop dramatically during the winter months here in Europe. The temperature does not decrease very much, but somehow enough for them start a kind of hibernation.
Interesting feature of this species are the many colour varieties that are available: yellow shell with yellow body; yellow shell with dark body, dark shell with dark body, dark shell with yellow body, white shell with yellow body and blue shell with dark body. All these colour varieties are the results of the availability or lack of certain pigments. Crossbreeding these varieties is very interesting!


Pomacea canaliculata

Pomacea canaliculata
Brown Pomacea canaliculata snail.

Pomacea canaliculata
Typical deep, indented sutures of Pomacea canaliculata.
Laying eggs, Pomacea canaliculata
Female depositing eggs (Pomacea canaliculata).

Pomacea canaliculata is the second apple snail species I got in my tank.
At the time I bought these snails, I still had no clue about the existence of several species, but I quickly found out when I compared my new snails with the ones I already had (Pomacea diffusa (bridgesii)). This triggered me to collect more information.
One of the first things I noticed with these interesting snails is the deep suture and the orange eggs. And at the same time these snails made me clear why apple snails can be a real threat to rice fields and to the nice collections of water plants of many aquariist. While the Pomacea diffusa snails left my plants alone, the Pomacea canaliculata ate away my tank vegetation within a week.
Pomacea canaliculata is also a very easy snail to keep. It's less temperature sensitive than Pomacea diffusa (better resistant to lower temperatures) and these snails ate almost everything.
Egg production is not an all year round event. They only reproduce in the winter and spring (October-May). They eggs are bright orange and loosely attached to each other. The baby snails are much easier to raise then the Pomacea diffusa snails (they immediately do well on lettuce and other vegetables). The growth speed of these snails is remarkable: after 1/2 year they are about 4-5 cm diameter when the condition are good (high temperature, good water quality and 'lots' of food).
Although these snails are not known as very large apple snails (about 5-6 cm average) they can get huge if they are fed all the time (ad libido) (6-8 cm shell height). This is much bigger then the Pomacea diffusa (bridgesii) snails ever (around 5cm height max).
I do have some colour varieties, but these are less spectacular then the Pomacea diffusa snails. At the moment I have some yellow ones (the golden apple snails), a bunch of dark brown ones and some intermediates (green, dark and light body). In fact I bought some dark snails in one shop and yellow ones in another and got the in between variations by crossbreeding them.
In my own snail population, these snails tend to get older than my diffusa snails do. My oldest one at the time of this writing is about 3 years old and still doing well. Also these snails do not suffer from severe shell detoriation as my diffusa snails do when getting older.


Marisa cornuarietis

Marisa cornuarietis
Marisa cornuarietis.
Marisa cornuarietis
Marisa cornuarietis shell.

Marisa siphon
Often overlooked, but Marisa cornuarietis certainly has a breathing siphon, although much shorter than in the Pomacea species.

Marisa siphon
Marisa cornuarietis is not selective when it comes to a mating partner and mounts other species as well (in this case a Pomacea flagellata snail).

Marisa cornuarietis is easy to recognise due to its flat shell shape. It's often called the Colombian ramshorn or the Giant ramshorn.
Renate Husmann was so kind to send my a whole collection of these snails (thanks!) by mail. Besides the natural striped snails, she also provided my with an interesting variety that lack the dark stripes on the shell.
From day one, these snails never gave me any problems as long as the temperature stays above 20°C. They are less capable of surviving in colder temperatures than my other apple snail species are. Not strange as one realises that these snails are real tropical animals, whereas for example Pomacea canaliculata is rather sub-tropical.
Besides their shell shape, these snails differ from many other Ampullarid snails by the fact that they deposit their eggs in a gel-like substance in the water. Because the eggs are transparent, one can look at the developing snails inside the eggs. What's even more, you can see the little snails walk around inside the eggs, especially in the last days before hatching starts. Also interesting to see is how the eggs swell over time until the little snails walks inside a thing bubble of around 5mm diameter.
Just like Pomacea canaliculata, these snails eat nearly everything that is somewhat digestible and not fast enough to escape from them.
The most exiting experience I had with these snails was an sinistral specimen I noticed one day. In this case, the snail was left-turned instead of having a normal right-turned shell. Better said: this snails was a mirrored version of its siblings. Sadly enough, this snail died after a few months, so I never had the chance to see if I could get this snail to reproduce and what the effect would have been on their offspring.
Like the Pomacea diffusa snails, these snails also tend to have severe shell detoriation when growing older. Luckily, at the other hand, the snails mostly manage to enforce their inner layers; so complete shell disappearance does not occur.
When it comes to reproduction, marisa males are apparantly not very selective in their selection for a snail to mate with. In my case, the marisa snails mount the Pomacea diffusa (bridgesii) snails as well the Pomacea flagellata snails.


Pomacea flagellata erogata:

Pomacea flagellata erogata
Flagellata erogata, shell from underside.
Pomacea flagellata erogata
Flagellata erogata, shell, back view. 
From underside
Live specimen (from Palenque, Mexico), subspecies erogata (Fisher & Crosse, 1890).

This interesting apple snails species was send to me by Harald Auer (thanks!), in early 1999. The snails I got where the second generation of snails caugth in Palenque, Mexico. It was a hard time to determine these snails, but finally I managed to do so based on their shape, colour and geographic location. While Harald had good results with these apple snails, mine did not do very well. Although they did grow well at fist, they stopped growing after a while and became gradually less active. One after another died and despite the fact that I got a second batch in August 1999, I did not manage to keep these snails alive, let alone to get them reproducing. In summer 2000, my last one died. Harald reported similar problems as well. For some reason, it's hard to keep these snails in captivity. Maybe they have need for very specific needs to remain healthy.


Pomacea flagellata flagellata:

Pomacea flagellata flagellata
Flagellata flagellata, shell from underside.
Pomacea flagellata flagellata
Flagellata flagellata, shell from above (from Balneario, Teuchitlan, Mexico).
Pomacea flagellata flagellata
Flagellata flagellata, walking around.

I acquired this Mexican snail species in January 2000 from Brian Kabbes (thanks!). The beauty of these snails immediately attracted me: their dark shell with smooth surface. I believe they are amongst the more beautiful apple snail species (in my own opinion at least).
The snails grow quickly and around summer 2000 I got my first egg clutches. These eggs are indistinguishable from the Pomacea diffusa (bridgesii) eggs. The eggs hatched within 2-3 weeks and after a while I had a large pool of Pomacea flagellata flagellata snails. This was a big difference from what I had experienced with the Pomacea flagellata erogata I had before.

repaired shell
Sex differences in adult Pomacea flagellata flagellata snails.
The female is larger and has a straight shell opening, while the male (left) has a extended shell lip.
Dead snail
A Pomacea flagellata with white spots on the foot and body. These lesions expand at the border and slowly heal somewhat in the center. In the case of the author's snails, many affected snails died.

If one asked me to tell something remarkable about these snails, I would mention the striking sex difference between the male and the female snails. More specifically the male has a trumpet like shell opening, which is absent in the female. I haven't read any article yet that mentions this obvious difference, although a sex difference has been reported in Pomacea canaliculata, although less visible (only a rounder shell opening in the male snail).
Despite the good start I had with this species, after a while I noticed small white spots on the foot of these snails. These small white patches look like scar tissue and slowly progress. In severe cases, the snails appear to die from this condition. I still have no clue what the cause could be. I've tried to play with the temperature, I switched food and raised and lowered the pH, but these snails keep developing these discoloured regions on their foot and other places of their body. As the other snail species do not get these patches, I gives me the impression I'm dealing with a deficiency in their tank habitat rather than a parasite or another microorganism. On other words: something is missing, but what? Hopefully I manage to get a thirth generation, which hopefully has less problems and maybe I can get rid of this white path disease due to selection of the more resistant snails. We'll see.
February 2001: Things seem to get better. The white patches on the snails disappear somewhat and some snails have almost no spots. They grow well again and I expect them to reproduce within months.
April 2001: Snails are going fairly well. I do expect eggs within the next months :)
Update 2007: These snails did not survive.


Asolene (Asolene) spixi

Asolene (Asolene) spixi.
Eldorado do Sul, Rio Grande do Sul, Brasil. 06-05-2000.
36 mm high.

Same snail, back view.
Asolene (Asolene) spixi.

Around October 2000 a snail package arrived from Brazil. To my great happiness, it contained 3 Asolene spixi and 2 Asolene (Pomella) megastoma snails, alive! (Thanks Fabio!).
The spixi snails have (in my opinion) a very beautiful striped shell. The base colour and the sharp stripes give the a resemblance somewhat comparable with Marisa cornuarietis. And suprisingly enough, the Marisa snails thought the same as some males mount the spixi snails. :)
Anyway, the spixi snails are not amongst my most active snails. Nevertheless they eat reasonably well. When they walk over smooth surfaces they exhibit a strange way of walking: they extent and contract their foot, which makes their walk step-like. They haven't grown much since I got them (less then 1/2 cm shell addition near the shell opening in 3 months).
Good news: the snails started to mate in March 2001 and deposited eggs in April, which have hatched now in May.
The eggs are indistinguishable from Marisa cornuarietis eggs.


Asolene (Pomella) megastoma

Asolene (Pomella) megastoma.
Uruguay River, São Borja city, Rio Grande do Sul, Brasil. 25-01-2000.
73 mm high.

Same snail, back view.
Asolene (Pomella) megastoma.

Together with the Asolene (Asolene) spixi snails, 2 Asolene (Pomella) megastoma snails arrived. It was the first time I saw these snails alive. I did had some specimens in formaline, but no living snails.
What I like most in these snails is their unusual shell shape: very broad shell opening (aperture), with a flat shell spine. Furthermore they have a large head, with the tentacles far apart. Their eyes are on the small size and are visible as tiny black spots on top of the eyestalk.
They walk slowly and keep their head constantly beneath their shell. In fact, you'll only see their tentacles and part of the proboscis (snout).
And while my Asolene spixi snails only grow very slowly, the megastoma snails are fast growing snails. Not surprisingly if one keeps in mind that my snails were only 3 cm in shell height, while they can easily grow to about 10 cm height. In other words, my snails are juveniles (young snails).
I hope that my two megastoma snails are of different sex, so I can get some babies in the future (as I would like to see in all my snails).
Until now, these snails did not give any problems and appear to be easy snails to keep. But time will tell...
Update 2007: These snail eventually died, without offspring.


Pomacea maculata; Corrected to Pomacea haustrum.


  Pomacea maculata
Pomacea haustrum.

In August 2000 I finally managed to get some Giant apple snails (Pomacea maculata) mailed to me by Sandra Shumilla (Thanks!).
One of the first things I noticed when I saw these snails for the first time, was their resemblance to Pomacea canaliculata, but somehow they were different in some ways as well. The shell of my 10 small maculata snails was higher then a canaliculata of same size. They look somewhat like a stretched canaliculata, with less deep sutures and a less rounded appearance. Sandra also mentioned the green colour of their eggs instead of the orange eggs of canaliculata. Besides the difference in shell shape, these snails also have a longer siphon, especially visible when the snails have their siphon at rest. In a canaliculata snails, the siphon is very short when not in use and eventually opens up to a be no more than a mantle fold. In maculata, however, the siphon is folded in front of the foot when not in use.
The snails I got in August 2000 grew very fast since that time. Their size increased from 2-3 cm height to 6-7 cm in 5 months.
Although their appetite is less extreme than in Pomacea canaliculata snails they are good eaters of all kind of vegetation.
April 2001: I have my doubts whether these snails are Pomacea maculata as they could well be Pomacea haustrum as well. It's rather hard to tell the species without knowing where they originally come from... I need to get some more info and/or wait until the snails are fully-grown. I do know at least that Pomacea haustrum does not grow above 12 cm shell height.
Juli 2001: I'm getting more and more convinced that these snails are not maculata but haustrum. This because: 1. the colour resembles haustrum much more than maculata; 2. Haustrum has green eggs as well; 3. Haustrum has been reported in Florida, brought there with the aquarium trade, while maculata has not been reported yet. 4. Their growth slows downs and they show sign of getting ready for reproduction, while they are about 8-9 cm at the moment.
Update 2007: After we moved to Belgium in 2001, the haustrum population declined and around summer 2001 I had none left.



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