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From time to time you may experience problems with your snails. Very little is known about what these illnesses are, what causes them, and even less is known about treatments. Unfortunately it seems more time is spent on increasingly more ingenious ways to kill them.

Because of this, the following information is a mix of whatever research is possible and available, theory and hypothesis, logical thinking and the result of various discussions with a large group of snail owners. It is with the help of the community at large, that these problems can at least be documented. Where possible I have tried to link to example incidents.

Hopefully, we can find some effective solutions to the majority of these problems but for now I'm afraid you'll have to be content with various suggestions and discussion.

Deep Retraction/Malnutrition


When a snail retracts deeply into its shell but doesn't show produce a calcareous cover there is something wrong. The first thing to do is to check the obvious: Inactivity, Sealed In and the Pests section of this problem guide generally to rule out these possibilities.

Still reading? OK, the cause of this problem could be a number of things. So far, attempts at understanding it have failed and each possibility has logical reasons why it could be and logical reasons why it couldn't. I'm gonna attempt to explain this for each possibility using examples and detailing the various reasoning and discussion behind it. I have also documented the attempts that have been made to solve or limit the problem. For now I have called this Deep Retraction Syndrome until we can better explain it.

This name is perhaps a little misleading in that on the one hand the snails wish to retract, that much is clear, but I think the deep retraction that alerts us to the problem is the result of malnutrition rather than the snail managing to squeeze further in the shell than is normal for its body size. For many of us, this is the first real symptom noticed because the problematic snail lives with other snails and so lack of eating or some inactivity can go unnoticed perhaps for longer than in a snail kept in isolation or paired.


To my knowledge this problem so far has been 100% fatal in all snails that showed more than a couple of the following symptoms:

  • Early Symptoms - Loss of appetite. Less activity, long periods spent buried. Snail sometimes twists in its shell towards the breathing hole.

  • Mid-term Symptoms - Deeply retracting, snail can still be woken up but will only stay out for brief periods of time. Loss of weight, body begins to look too small for the shell. Snail struggles to pull the shell around. You may find the snail upside down where it has retracted and fallen to the floor. Shell loses colour (hard to explain but I have noticed that the shell became lighter and more bleached looking as time went on).

    At this stage in a few cases the snail has actually eaten a little for a few days, which seemed to suggest the snails were getting better. It didn't last...

  • Before Death - Even deeper retraction probably due to the decreased weight and size of the body. Hard to wake up even with a lot of attention and stimuli. Snails takes longer and longer to stir and retracts again almost immediately.

Possible causes: reasons for and against


It has very recently (10/2005) come to my attention that the problems could be caused by an overly hygienic tank. This would explain why more snails got ill, because my care routine so far has been ultra clean, for fear of it being some sort of bacterial infection. But it may be the very cause itself.

The Scientic Paper "The Life of Achatinidae in London - Presidential Address - R.H. Nisbet Proc. malac. Soc. Lond (1974)" was a study involving between 200 to 500 Achatininae at any one time of both Achatina and mainly Archachatina (in particular Archachatina marginata var. ovum) for over 20 years. There are a couple of particularly interesting sections from this document which may shed some light on this problem. Unfortunately it is not the main focus of the paper and, coupled with the detrimental results experienced which ultimately ended the experiment, it was not discussed in great detail. The relevant bits are as follows:

"There is some evidence for suggesting that each snail may have a cycle of feeding activities, viz. the ingestion and comminution of food that is then defecated without, or with very little, digestion; the ingestion of soil - and some food - followed by digestion and defecation; and, finally a period (one night?) of little intake of food followed by a day when the faecal string consists of material from the digestive gland. There may be a 3-day cycle, that raises problems in the feeding of these animals. It also raises the question of the animal's possible need for regular ingestion of soil flora and fauna together with rotting food material. In one useful but hazardess experiment a vivarium was provided with double-sterilised soil, all surface soil and faeces were removed three times weekly and the loss replaced with more sterilised soil. The first sign of trouble was a cessation of oviposition in a formerly actively reproducing population of mixed ages. In three weeks the snails then ceased to feed and became lethargic and, in the following month, thirteen out of twenty-four snails died. At this point the experiment was terminated."


"Cleaning should remove only the excessively polluted soil and food debris. Hygienically clean tanks lead to cessation of feeding and reproduction, and ultimately to the death of the snails. A tendency towards slum conditions has to be aimed at, especially in the case of A. panthera"

So, it would seem that the snails need bacteria and other microbes to be healthy. Tanks kept too clean will obviously remove this necessary life and could lead to poor health in the snails. However, it must be noted that so far I haven't heard of a single Archachatina suffering these problems, including my own. It stands to reason that the experiment detailed in the paper included Archachatina marginata var. ovum, being the majority of the snails included and reared although this is not explicitly stated.

That said, the information should not be discounted because a viral problem (see below) could be exasperated by this, in that snails experiencing health issues related to hygienic conditions would be more susceptible to any viruses they come into contact with. The question that remains is how dirty is dirty-enough? The study itself addresses this problem and it seems considerable time was spent trying to find optimum conditions. Eventually they fed and cleaned the snails once a week, so that food was allowed to go bad, giving the snails chance to eat it. This may not be acceptable in pet conditions due to excessive mold, so perhaps food replacing every few days would be fine, with one clean-up that removes faeces once a week. The substrate should not be sterilised as often, perhaps only once every 1 or 2 months.

It is hard to recommend this course of action but anyone suffering this retraction/malnutrition problem should consider this information carefully.

Weak Genes

After my first encounter with this problem everything seemed to point towards this. The affected snails were (probably) inbred Achatina fulica siblings and the other species they shared a tank with with were fine. This was supported by the fact that some of their siblings that had been re-homed months before started to show the same problems. However, in this case, a further unrelated snail got ill and died in a similar way. Also, in one case the gut had been expelled which seems unlikely to have been caused by bad genes, if it is related I hasten to add.


My snails were all doing fine, I had recently found a great solution to a minor mite problem I had, so the snails were completely mite-free. They were also captive-bred and hadn't been mixed with any wild ones so worms seemed unlikely. I found nothing in the snails faeces and a close inspection of every snail found no visible problems. I checked inside the breathing hole with a torch and a magnifying glass and found nothing.

Genetic Kill-switch

I had this idea when all the cases seemed to be snails of a certain size, 3-4 cm+. In nature certain things seem to have a kill-switch. Saplings for instance, that seem to be healthy will often die for no reason after a year of healthy growth. We re-home our babies and it is unlikely we ever keep a full clutch to see how many make it to adulthood. This is closely related to weak-genes, as babies that would not normally make it survive for a while, and snails that would not breed successfully manage to in captivity without wild pressures.

This reason has recently been scuppered but perhaps not completely killed by the discovery that some people have seen this problem in older snails. Remember, we could be seeing more than one problem occurring.

Bacterial or Viral Infection

At the moment this is the most likely answer though there is some contradictory evidence. About 6-8 weeks after the two fulica had died, a Achatina immaculata baby in that tank got ill and died, though much quicker. The ill ones had been quarantined from the first signs of illness and the tanks and all the equipment had been sterilised and cleaned, and the substrate changed. Either this snail had already contracted the illness or the death was unrelated, as the snail was actually a runt.

I was maintaining strict hygiene, washing my hands between handling from different tanks, and keeping equipment separate and all seemed well. And then an Achatina immaculata var. "two-tone" baby in a completely different tank showed signs of the illness. He was removed to quarantine immediately, everything changed over and sterilised and so far there have been no more occurrences, though I do expect more. The problem spanned more than one tank but did not affect the majority of snails, and in my cases they were all babies, 3-6cm in size.

I've enquired extensively about this problem to more experienced people than me and there have been many reports of similar problems, though adults in some cases. What seemed to prevail is that not all the snails were affected and the cases were quite a while apart. Conversely, Pseudomonas infections apparently wipe out snails kept in captivity very quickly.

If it is an infection then the incubation period is quite long, I estimate it to be longer than 4 weeks, more like 6-8 weeks. It is possible that the snails carry the infection and are only infected at certain times, perhaps when weak due to other reasons.

I'd also like to point out that my snails had already been living together for months, if one had been the carrier when sent to me, surely a bacterial infection would have manifested earlier? It is impossible to predict where this problem came from, as I have had snails from many different sources, they have at times spent time with the others and I originally used the same equipment interchangeably.

It is for these reasons that I think the nature of the problem is a virus as oppose to a bacterial infection. I think a bacterial infection would have been quick and more devastating initially, and probably easier to restrict. A virus would explain the apparent randomness of which snails show symptoms. It also means that most of my snails have probably got the virus and it is either dormant or they are holding it off. If it is a virus then the only real treatments that will help are anti-virals and immune-boosting substances for treatment of ill snails and as a preventative for the rest of the population.

Treatments and Preventative Measures

Loss of Appetite

Every conceivable food has been tried. Every fruit and vegetable possible, all the cereals like hemp, oats, pumpkin seeds, chicken mash etc. and both parboiled and cooked food. It seems that the snails are simply not interested in food and no amount of tempting them works. I was hoping there would be a particular type of food that could get them interested. So far, if such a food exists I haven't found it. Clearly, regardless of what the ultimate cause is, alternate ways to keep the snails strength up are needed. You have few options really:

Try and feed the snail by rubbing its mouth with liquid food. This idea is based on the principle that some may be swallowed involuntarily. A vitamin solution would be best here, because we need the most nutrition per drop seeing as little will be taken in.

On the other hand, snails absorb water through their bodies so it is possible that certain other things can permeate the skin. I do not know the micron size that will pass through the body, or the micron sizes of the various nutrients that may do them good. But we can try. Bathe them in a vitamin enriched solution, preferably sitting them in some to give it chance to penetrate.

I'm not sure whether these methods are something you need to do straight away, but I can't see any harm in them. Remember, it is no good rubbing neat vitamin solution on the mouth as too many vitamins are poisonous. Water it down quite a bit.

Lack of activity

I had the overwhelming urge to constantly wake my snails up. I had the feeling that the more they were awake the better chance they had. On reflection I realise this is probably incorrect. It is true to say that leaving them retracted all the time is far worse as they will ultimately die. But I now think that because the snails get progressively weaker, you need to conserve their energy for the times you need it to count, such as when you are trying to treat them or get them to eat.

In the early stages getting them out of their shells is only a little more difficult than a normal healthy snail. A gentle prod or a spray will bring them out to investigate. In the later stages it becomes very hard. A rather drastic, but sometimes necessary method I have found is to turn the shell opening up and fill it with water. Wait 10 seconds, empty it and let it drain and then repeat. The snail will realise it cannot breathe and will be forced to come out of the shell. I think this is why natural history collectors drown the snails for preservation, because the body extends. Don't worry about drowning the snail, they respirate very slowly, so 10 seconds at a time isn't gonna harm them, just allow the water to drain away each time because some will get in the breathing hole. Besides which, at this point it needs to be done.

Treatments tried

Bathing, including washing inside the breathing hole.

This is more related to activity. Bathing always increases activity and hopefully freshens the snail up. Standard practice of care for ill snails, I see no reason to discontinue this. Good hygiene in this respect can do no harm although over-zealous hygiene in the conditions they live may be detrimental (see above).

More heat, less heat, more humidity, less humidity.

I did find that putting one of them in a sealed container on some gentle heat, which causes very warm and humid conditions did trigger more activity and a little eating but this was sporadic and I have no real results to show for it. It is a positive step however. If you do this make sure you air it out frequently.

Vitamin solution

I have been including small amount of vitamin solution in their mixed food but as they are refusing to eat this has proved to be rather futile. So instead, I decided to sit the snail in water with a few drops of vitamin solution added. I have no idea whether this helped the snail but I hoped that some nutrition was absorbed or even mistakenly swallowed.

Note: Be very careful, on one occasion it caused a very strange swelling of the snail like an allergic reaction. Washing it off with water caused the swelling to go down immediately and the snail seemed exactly the same as beforehand. Having done this before successfully, I can only conclude on this particular occasion I had added too much vitamin solution.

Green tea (Camellia sinensis)

I sat the snails in the tea and bathed them in it. I also hoped the would drink it, even if accidentally. Green Tea features on the the list of plants Achatina fulica has been found eating. As they eat the leaves raw (their strongest form) I decided tea made from the leaves would be perfectly harmless and this definitely seems to be the case. I have tried making my snail mix with green tea instead of water. I have witnessed healthy snails eating the resulting paste with no adverse effects.

Aloe vera (Aloe barbadensis)

I tried this as a food and I also rubbed some of the gel on to their mouths. Early on in my struggle I had suspected they may have sore mouths and were unable to eat so I used the gel as a soothing lotion. As time wore on I also tried Aloe vera for its anti-viral, anti-bacterial and immune-boosting properties. I have seen no ill-effects from this but once again, I cannot tell if it helped at all.


After my fourth and so far last snail got ill I cleaned everything and moved to coir instead of peat. And I also bathed the snails heavily in a weak Melafix/Water solution. The idea was to kill off any bacteria on the snails so I knew the tank was really clean. That way, the only possibility for re-infection/transmission is from the internals of the snails and faeces. And of course external contaminants from water and food. I am holding my breath to see how it works out. And I am continuing an over-zealous care routine with all my snails until further notice.

Steroid tablets

I was fortunate to receive some steroid tablets from Linda at Snails2Die4.com (link dead) to try and get them eating. I powdered them and mixed them into a paste to try and feed. The snail actually appeared drank some of the solution. I also bathed the snail in the hope that some would be absorbed although this is highly unlikely as the steroids were made with white binding powder. As yet, I haven't seen any improvement because of this and I didn't wish to dose too heavily so it hasn't been tried extensively yet.

Other treatments

Antibiotics (bacterial) - Untried


Latin Name Common Name Anti-
Allium sativum Garlic Yes Yes Yes
Aloe barbadensis ** Aloe Vera Yes Yes Yes
Arctostaphylos uva-ursi Uva Ursi Yes Yes Yes
Arthrospira platensis * Spirulina Yes Yes Yes
Astragalus membranaceus Astragalus - - Yes
Calendula officinalis * Marigold Yes Yes Yes
Camellia sinensis ** Green Tea Yes Yes Yes
Chlorella pyrenoidosa * Chlorella - - Yes
Cimicifuga racemosa Black Cohosh Yes - -
Cinnamomum zeylanicum Cinnamon Yes Yes Yes
Echinacea purpurea Echinaecea - - Yes
Eleutherococcus senticosus Russian Ginseng - Yes Yes
Glycyrrhiza glabra Licorice Root Yes Yes Yes
Hydrocotyle asiatica Gotu kola Yes - Yes
Hydrastis canadensis Goldenseal Yes Yes Yes
Hypericum perforatum St. John's Wort - Yes Yes
Ilex paraguariensis Yerba Mate - - Yes
Linum usitatissimum * Flaxseed Oil - Yes -
Magnolia officinalis Magnolia Yes - -
Matricaria recutita Chamomile Yes - -
Melissa officinalis Lemon balm Yes Yes -
Olea europaea Olive leaf Yes Yes Yes
Panax ginseng Asian Ginseng - Yes Yes
Polygonum multiflorum Fo-ti Root Yes - Yes
Rhodiola rosea Rhodiola - - Yes
Sambucus nigra * Elderberry Yes Yes Yes
Silybum marianum Milk Thistle - - Yes
Taraxacum officinale Dandelion Root - Yes -
Uncaria tomentosa Cats Claw Yes Yes Yes
Urtica dioica * Nettle Leaf - - Yes
Vaccinium macrocarpon * Cranberry Yes - -
Vaccinium myrtillus * Bilberry Yes - -
Vitis vinifera Grape Seed Yes Yes -
Withania somnifera Ashwagandha Yes - Yes
Zingiber officinale Ginger Root - Yes -

* Known to be safe.
* Tried. See tried treatments for results.

Caution: Although it seems likely most of these herbs would be safe for snails, it would be wrong to automatically assume they are. Caution is needed and further reading recommended for those interested in using them.

Obviously all of these require ingestion so the feeding method described above may have to be resorted to unless you catch it early enough. If we could find a safe, possible preventative it could be added to part of our snails diet generally.

It is impossible for me to try all these herbs and I certainly hope that the problem doesn't progress to a situation where I have used so many. I am hoping that if others experience similar problems, these herbs can perhaps be tested. If you are battling this problem, feel free to contact me by clicking here.


This recent wave of problems certainly points to a viral infection but I don't think the symptoms are exclusive to this problem. Descriptions on "The Snail Pages" (http://www.geocities.com/sarkymite/snails/ - link dead) (see Further Reading) of unrelated illnesses are very similar. I think an accurate assessment is that the symptoms we see are of malnutrition and starvation, which is ultimately what kills them.

Currently I think the only realistic way to tackle this problem is through prevention, make sure your snails are healthy while they are eating perhaps by adding nutrients or even anti-virals and immune boosters such as green tea. If you see any change in eating habits isolate immediately so you can monitor the situation. Ultimately, the only way to help an infected snail is to get it to eat and at present no "magic" food has been discovered; it does seem that ill snails simply refuse to eat.

Additional Notes

So far, the problem seems restricted to the genus Achatina because there have been no reports of any Archachatina suffering these symptoms and my other non-African snails appear to be unaffected. However, that is not to say that they can't carry it if the problem is viral. My fear is that it will, or indeed has, already spread to some other more rare species and that may see the end of them kept in captivity. I have learnt a few very good lessons.

Firstly, I have too many snails. Things are fine when all is well, when some need a time-consuming and extra careful care routine it becomes a struggle to keep it up.

Secondly, keeping different species in separate tanks is a good idea if you have the space. I wanted more snails in a large tank instead of smaller tanks with only a few in each. I think this is preferable if you have the space and money for larger tanks but if you're like me and prefer to keep two of each species, you may end up losing one and being left without a breeding pair.

Lastly, a lengthy quarantine period needs to be strictly adhered to for new arrivals. I would suggest 3 months to be sure. This is very inconvenient but believe me, when your isolating snails because they're ill, you end up with more tanks and more inconvenience. However, if it is a virus, we have no idea how long the virus remains contagious so any snails you own would be a risk to new snails and vice-versa. Therefore, this problem in many ways is unavoidable.

As I mentioned at the beginning, this problem could well be a number of different ones confused. I am hoping that now it has been documented, given a name, and the symptoms described we can spot this problem earlier and get more useful and detailed information about it.

Further Reading

To search the forum for threads definitely relevant to this problem click here.

To search the forum for threads that may be relevant click here.