Health Problems & Solutions – Donya Quick 1
Health Problems and Solutions
Because apple snails are a relatively new addition to the aquarium trade, there is
not much readily available information on how to diagnose and treat their illnesses. Not
much is known about what causes some of the most serious health problems among apple
snails, and as a result treatments for various conditions either do not exist or are purely
experimental with a high fatality rate. Currently there is no such thing as a “snail vet,” so
many owners of these animals have been forced to come up with solutions to problems
on their own.
Shell problems
Shell Deterioration
This is by far the most common problem new owners encounter. How it is
expressed varies among individual snails, but it always involves a flaking or “rotting” of
old shell growth that exposes the white calcified interior. It can be caused by water
conditions, excessive scratches on the shell, or even by other species of snails and fish
eating away the outer shell layer.
Shell deterioration is almost always caused by poor water quality: a ph below 7.0
and soft water. A low ph will not show immediate damage on all shells, but if a snail is
raised in acidic water, the shell it grows will later
deteriorate regardless of actions to change the
water quality. It is often a symptom of snails kept
for prolonged periods of time in pet stores, since
they are rarely supplied with calcium and usually
not kept in alkaline water.
For most cases, no treatment except a
watchful eye is necessary for a deteriorating shell.
Snails are capable of reinforcing exposed calcified
areas with more calcium, and it will usually not
affect the well being of the animal. In rare cases
the deterioration will continue right to the soft
tissue, whereupon the tissue will calcify and form
new shell. This is not a problem in itself, but it can
sometimes lead to the formation of calcified
tumors or calcified internal organs, both of which
can severely compromise the snail’s health. If the
This large canaliculata shows shell deterioration in
the old growth. After it was purchased from a pet
store, it put down much better new growth that
never showed any signs of wear. Because the old
growth was of inferior quality, it was impossible
to prevent its eventual deterioration, even with
improved water quality.
deterioration will not stop and begins to risk going
through to soft tissue, clear nail polish can be
applied to the area (do not touch the snail’s skin
with it, only the shell!) to prevent further damage.
It will give a slight “glazed doughnut” appearance,
but the snail’s risk of further damage to the area
will be greatly decreased.
Health Problems & Solutions – Donya Quick 2
Shell breaks and Fractures
In minor cases, this just involves chipping of the shell rim where new growth is
occurring and does not require any intervention to heal. However, if the break occurs in
old shell growth where the snail cannot fix it as easily, depending on where the specific
break location and the severity it can ultimately be fatal. There are a few basic kinds of
shell breaks:
o New growth fractures/breaks. No
treatment is necessary for minor
cases of these unless they go into the
old growth, in which case they can
be considered an old growth fracture
or break. If the new growth looks
like a crushed hardboiled egg, liquid New growth – open
New growth – crushed shell
and/or edible calcium supplements fissure and chips at the
will be necessary to help the snail rim
repair itself, though it will most
likely not eat.
o Old growth fractures/breaks. A shell patch (see the
following section on shell patching) may be required if
it is over the heart or other internal organs, or if a piece
breaks completely free. Large breaks are usually fatal,
especially if a large piece comes completely away from
the body. If the break looks like a crushed hardboiled
egg and is not fatal within a few hours, liquid and/or
edible calcium supplements will be necessary to help the
snail repair itself, though it will most likely not eat.
Old growth – closed/healed
fissure and breaks
o Spire fracture. If no part of the spire has come away, and
the break resembles a hairline fracture that does not wrap
around the spire completely, then a shell patch may be
necessary (see the section on Shell Patching).
o Broken spire. In this case the spire breaks completely free,
or crushes. It is often the result of a bad fall taken or a longstanding calcium deficiency. Unless
the underlying tissue is already
calcified, chances of recovery are
incredibly slim, and almost 100% of
the time the condition is fatal within
a day or two. Sometimes the tip of
the spire will chip away or break off,
usually following shell deterioration; Old growth – severe shell
in these cases the underlying tissue is deterioration with a broken,
almost always calcified so no patching calcified spire
Fractured spire
Broken/Crushed spire
with no calcification
Health Problems & Solutions – Donya Quick 3
is necessary, though further erosion due to ph could lead to more serious problems
exposing soft tissue.
Shell Deformities
Shell deformation is caused by an
injury to the mantle in some way that prevents
it from laying down new shell in a normal
pattern. Marisa cornaurietis is particularly
susceptible to this, and it is also most visible
in this species.
Because this condition involves
damage to soft tissue, the best and only
solution is to wait and watch. Most snails do
not die, unless the mantle damage persists and
a large “rift” forms in the shell that is never
filled in. In those cases, the snail usually lives
for a while but will die unless a shell patch is
possible (see the following section on shell
patching). Snails that survive and repair
themselves completely can live long happy
lives, though if the deformity constricts the
snail’s growing body in any way it can lead to
internal problems or difficulty retracting into
the shell.
“Broken,” a male Marisa cornaurietis exhibiting a long
history of shell deformities and deterioration. Despite the
odd appearance, he reproduced successfully to have
children with a female who also had a shell deformity
This female Marisa developed a shell constriction that
prevented her from retracting all the way into her shell, but
she still managed to lay fertile eggs and live a long life.
Thin Shell
A thin shell is hard to spot for the new snail owner, especially since snails will
sometimes put down thin new growth that later becomes normal thickness, but the
condition becomes easy to spot with
other snails available to compare. Thin
shells are extremely fragile, and can
have a washed-out or faded appearance.
Thin shells are particularly prevalent
among blue, purple, red-brown, and
ivory snails. In those colors, the snails
have naturally less-sturdy shells, but
they are also susceptible to disorders
where the shell cannot be properly laid
down due to constant re-uptake of
These two purple snails died from excessively thin shells that
calcium deposited in the inner shell broke repeatedly. Note the lack of color intensity and the faded
layer, regardless of the amount of yellow-white areas characteristic of this condition.
calcium fed to them or dissolved in the
water.
Unfortunately the first sign that a snail is having trouble with a thin shell usually
comes when the snail is picked up and/or dropped a small distance of less than three
inches and the shell shatters either in-hand or when it lands. These cases are always fatal
Health Problems & Solutions – Donya Quick 4
in the end. If the first break doesn’t kill the poor thing, the second, third, fourth, etc.
eventually will. These snails break very easily, and sometimes even a gentle push from
another snail can crush them if they are against a hard surface. If the snail is a female, she
will have difficulty breeding. The shell risks cracking under the strain a male puts on it
while mounting.
Operculum Separation
This condition involves the part of the foot that produces the operculum pulling
away from its normal attachment site. Depending on just how much the foot and
operculum separate from each other, they may be able to reattach or the foot will be able
to produce a new “ledge” of operculum. In the latter case the resulting appearance is of
two operculums until the new one grows beyond the old one. The old one may or may not
chip off. If the operculum separates completely and the foot is left 100% unattached, the
snail will probably not survive long enough to grow a completely new one, though this is
a very rare problem.
Operculum separation on a live snail should not be confused for the natural loss of
the operculum on a dead snail. On dead snails, the operculum usually loosens and falls
off within a day or so if left in water—by which time the snail will smell absolutely
terrible.
Operculum Damage
Operculum damage happens when a snail’s operculum gets dings and chinks
taken out of the rim, without ever pulling free of the foot. This is a very minor problem,
and will only lead to an unsightly and lumpy operculum, but will not adversely affect the
snail in any way unless it leads to operculum separation.
Soft Tissue Problems
Lost Tentacles
If snails are kept in with bitey fish, this is inevitable. Snail tentacles look like
delicious large worms to most fish and they will act accordingly. Fortunately snails are
equipped with remarkable regenerative capabilities and can replace lost tentacles
repeatedly, though after enough nipping they will not grow as long as before. Of course,
while snails can re-grow lost tentacles many times, fish should not be allowed to harass a
snail past one or two incidents or it will add additional stress to the snail and compromise
its activity and overall health.
Damaged Foot/Body Tissue
Bites and snicks taken out of a snail’s foot are cause for much more worry than
lost tentacles, though there is not much that can be done for the snail short of removing it
from whatever caused the foot/body damage and adding liquid calcium to relieve any
stress it might have from shell growth and repair. If enough body tissue is destroyed the
result will be fatal.
Health Problems & Solutions – Donya Quick 5
Fungus Infections
This is an easy condition to spot: the snail
will start showing discoloration on the bottom or
top of its foot that progresses to dark or light
colored “spots.” Unfortunately there is no cure for
fungus infections, since all available fungus
treatments for aquariums contain chemicals toxic to
snails. The infected snail should be isolated from
other snails to prevent spread of the fungus. Cold
water between 62 and 68 degrees Fahrenheit
appears to help snails recover from fungus
infections, although the survival rate of bad
infections is still low.
This snail suffered a bad bite to the back of its foot,
probably from another hungry snail.
“Warts” and Cysts
Mostly an occurrence among old P. canaliculata
snails, some individuals develop bumps on the foot,
face, and tentacles. The bumps may vary in size from
almost imperceptible to the size of a pinhead, and the
larger bumps on the labial or cephalic tentacles may
cause “kinks” in the tentacles. Although the condition is
unsightly, there is no evidence that it is transmittable to
other snails in the same tank or that it is connected to
any other health problems.
Cysts can often look very much like warts, but
in these cases there is an object imbedded inside the
tissue for whatever reason. They are visible as darkened
spheres in areas where the surrounding tissue is thin,
such as tentacles and the edges of the foot. When
This old male canaliculata developed
occurring in tentacles of young snails, cysts may cause warts after reaching sexual maturity.
bifurcations of the tentacles at the site of the cyst. The Despite the grizzly appearance, the warts
did not negatively affect his health.
cause of cysts is unknown, and most seem to disappear
with time if other infections, such as fungal infections, do not occur in the same area.
Cysts do not appear to be contagious to other snails in the same tank and do not appear to
be related to any sever health conditions.
Forked Tentacles / Forked Siphon
Forked tentacles occur during periods of growth, usually caused by cysts (see
above). They are nothing to worry about, and if nipped off by a fish they will grow back
normally. Forked siphons are also not a major problem, but a snail with a branching
siphon may require more space above the waterline to breath. The cause of forked
siphons is unknown, but they appear to be inherited in some cases.
Health Problems & Solutions – Donya Quick 6
Foot Atrophy
Shrinking of the foot, commonly called “wasting disease,” is a sign of severe
stress due to starvation and frequently other internal problems. It particularly occurs in
bridgesiis kept in conditions where they have nothing to eat for long periods of time. If
the starvation persists, internal organ damage can occur that is eventually fatal. If the
situation is caught soon enough most snails can recover
given unlimited access to food for one to two weeks. If
the snail continues to exhibit a shrinking foot or does not
improve, it will not be able to overcome the condition and
will die. Foot atrophy can also be a sign of internal
growths, sometimes calcified tumors, although they are
seldom obvious until after death.
Mantle Collapse
So far nobody really knows what causes this, but
it is fairly prevalent among snails in the aquarium trade.
When the mantle “collapses” it pulls away from the hard
shell, thereby giving the body and internal organs no
structural support where the separation has happened;
usually it happens on one side or the other, but both are
fatal. If the mantle collapses on the left side, the snail will
most likely only live a few hours and you probably won’t
find out about it until it’s already dead. The lung is
located on the left side and when the collapse causes it to
cave in, effectively suffocating the snail. If the mantle
collapses on the snail’s right side the snail may survive
for up to a week, but it will suffer in that time with
difficulty moving and breathing. The snail cannot
recover from this, and most people choose to euthanize
the animal rather than let it suffer. Euthanasia can be
accomplished by placing the animal in a freezer: since a
snail’s metabolism is dependant on the ambient
temperature, it’s nervous system will slow down and it
will loose consciousness before death.
Collapsed Lung / Water-Filled Lung
Sometimes the lung itself can cause problems
for apple snails, particularly for female snails that are
going in and out of the water frequently to lay eggs.
When the snail is out of the water, the lung is open to
the air for breathing. If the snail falls unexpectedly back
into the water and doesn’t close the opening fast
enough the lung can become filled with water. This is a
very rare problem since the lung is capable of closing
extremely fast, but when it does happen it can be quite
serious. Usually the only clue that something is wrong
The two ways in which a snail with a
collapsed or water-filled lung must be
rotated.
A snail with a normal lung. Note the
sack-like appearance and the opening to
the lung.
A snail with a collapsed lung. The
opening to the lung is closed and the lung
is flat against the shell.
Health Problems & Solutions – Donya Quick 7
comes from a change in activity: normally active or friendly snails will suddenly stay
closed up at the bottom of the tank and not move for several days. Inactivity can be
caused by numerous things, but it never hurts to check for a water-filled lung. The
remedy for this situation is to take the snail out of the water and let it sit in a safe place on
a damp cloth for several minutes. It should eventually open up and possibly start to move
around. The water may come out once the snail opens up, but if there isn’t a noticeable
amount that comes out then you will need to help the snail. Pick the snail up, spire
pointing upwards, and rotate it counterclockwise (when viewed from above on a dextral
apple snail) for several turns. Then, hold the snail with the spire pointing away from you,
and rotate it clockwise for several turns. These rotations should allow the water to come
out the opening of the shell if there is any remaining in the lung or mantle cavity.
Another problem that can occur is the lung actually collapsing in on itself. Again,
it is a very rare occurrence but afflicted snails normally require assistance to overcome it.
The symptom of this problem is usually a snail lying on it’s back stretching as far as it
can upwards and outwards. The reason for this posture is that the mantle cavity is filled
with water and has made the shell extremely top-heavy, thereby preventing the snail from
easily turning itself over. Snails with collapsed lungs should be treated in the same way
as snails with water-filled lungs: they should be allowed to sit on a damp cloth for several
minutes and then rotated in the ways described above. Following that they should be left
in shallow water so that they can easily re-inflate their lung with their siphon. If you put
the snail back in deep water before it’s lung is re-inflated it will have the same problem
all over again!
Tumors and Internal Organ Damage
These come in a variety of forms from benign bumps on the labial and cephalic
tentacles to large organ-damaging calcified internal tumors. The cause of most tumors is
unknown, though large bumps on the labial and cephalic tentacles tend to appear in
individuals suffering from a fungus infection. Even after the infection is gone, however,
the growths are permanent and do not get resorbed. Calcified tumors are prevalent among
purple and red-brown snails suffering from thin shell syndrome; tumors are also
frequently associated with damage of other internal organs, or the calcification of organs.
Because all of the fatal types of tumors and damaged organs are internal, and no
symptoms show until sudden death, there is no treatment.
Tumors that are internal are impossible to detect except in a post-mortem
dissection, which is both extremely smelly and offensive to many people. Calcified
tumors are usually found in the process of shell cleaning after the animal has died. The
tumor is revealed after the body is removed when a large chunk of hard bone-like
substance gets shaken out of the shell. Soft-tissue tumors are only visible on recently
deceased snails when taken out of the shell. The flesh decomposes in water and dries out
otherwise so quickly that it becomes impossible to tell the tumor apart from the rest after
more than 48 hours.
Everyone who has dealt with a deceased snail knows that there is no smell
comparable to that of dead snail, which is why it is the last test to see if a snail has left
this world or not. If you plan to do a post-mortem on a recently deceased snail, please do
it in a well-ventilated room, or preferably outside. If you find the smell offensive (which
Health Problems & Solutions – Donya Quick 8
most people do), use rubber gloves, preferably disposable ones. The smell of dead snails
is nearly impossible to get off of skin within 24 hours and hard to remove from a sink
within the same time frame. Keeping the snails submerged in water or occasionally held
under slow running water greatly helps to reduce the odor problem.
Parasites
Most parasites that apple snails can carry will never be seen inside the aquarium
because the species that are carriers are not available in the pet trade. However, there is at
least one type of parasite that can make its way into the aquarium through wild caught
specimens of apple snails from the southern United States. This parasite is the grub
worm, a type of fluke that can neither harm humans nor reproduce in the aquarium.
Grub worms are encysting parasites that hatch in the water and seek a snail host
first. Once found, they form a cyst on the snail, usually on the bottom of the foot. These
small cysts will appear white and contain a puss-like substance. Numerous flukes are
released from the cyst when it ruptures, and they will then move onto their next life stage
in a fish. If fish are present in an aquarium with infected snails, they will likely show up
with the grub worms as well (these worms are often listed in fish disease books, but the
snail part of their life cycle is seldom mentioned). The grub worms will encyst in the
fish’s flesh. Mechanical removal of the worm is then necessary, because the worms will
not leave on their own unless the fish is consumed by the next host: a wading bird. If no
wading birds come into contact with the fish, the fluke’s life cycle is broken and
reproduction is impossible.
Torn Columellar Muscle
Often associated with mantle collapse, this condition is
100% fatal. The columellar muscle is responsible for holding
the snail into its shell and retracting the body to close the
operculum. When the muscle is torn, the snail has no way to
hold itself into its shell and so it eventually falls out.
Sometimes this can result in a snail walking around “shellless,” but it will not survive that way. Death will come
eventually from either edema or suffocation due to a collapsed
lung. Because death is inevitable and can be drawn out for up
to a week, some owners may prefer to euthanize a snail that has
lost its shell from a torn columellar muscle.
A snail that has suffered a torn
columellar muscle and lost its
shell as a result. The lung is
collapsed, making a saddleshaped mark on the back.
Toxic Substances & Poisoning
A variety of chemicals can have a poisoning effect on apple snails. The most
common toxic substances to apple snails are chlorine, chloramines, fluorine, and heavy
metals—all of which can be found in tap water. If you do not have well water, be sure to
use a water treatment that takes removes chlorine, chloramines, and fluorine. If you have
acidic water, be sure to have your water tested for copper (most pet stores will do this)
Health Problems & Solutions – Donya Quick 9
and other metals if possible. If your water tests positive for dissolved metals, you will
need to get a water treatment that removes heavy metals. Not all water conditioners will
remove everything, so you may need to buy two! Death is incredibly fast from exposure
to these substances. Fish medications containing malachite green, salt, and metals will
also poison and kill snails.
Ammonia/Nitrite Poisoning
Just like with fish, snails are susceptible to toxic substances building up naturally
in the aquarium. These substances are ammonia, nitrite, and nitrate. In a fully cycled and
stable tank, ammonia and nitrite should never show up on a test kit and only nitrate levels
should rise over time before a water change. However, in the event something goes
wrong in a tank, snails can suffer from ammonia and nitrite poisoning. In either of these
cases, the snails will usually not show symptoms until the ammonia or nitrite levels have
gone high enough to kill most tropical fish.
The symptoms of ammonia and nitrite poisoning are as follows: inactivity, sitting
on the bottom of the tank, lying upside down, immobility, unresponsiveness (many snails
will appear dead and not respond until severely harassed), severely rigid or completely
limp foot, and sometimes swelling of the body where the mantle extends past the edge of
the shell. Often snails with ammonia or nitrite poisoning will sit on their backs with the
foot completely extended and flat, as though they are perpetually waiting to catch
something.
Treatment for ammonia and nitrite poisoning is fairly simple. The most important
thing is to clear up the water condition or remove the snail from the bad water and place
it in clean, treated water. Take the snail out of the water and let it sit on a cool, damp
surface for about 15 minutes. Unless the snail has a collapsed lung or other internal
problems, it will eventually become more mobile and start walking around. Any swelling
will usually be gone by 20 minutes. After the snail shows marked improvement, put it in
clean water or back in the tank if the water condition has been fixed. Keep an eye on the
snail as it may repeat the behavior if the water is not to its liking. If the condition does not
improve, repeat the treatment. If the snail refuses to open up and three treatments have
passed, put it in clean, treated water and wait until the next day to try again.
Health Problems & Solutions – Donya Quick 10
Shell Patching
In the event that a snail breaks its shell to the extent that it cannot repair itself, a
shell patch will be necessary. Patching is a permanent fix: once the patch is applied it
should never be removed. You will need the following:
o Marine epoxy putty – be sure it isn’t liquid epoxy!
o Microwaved eggshell to cover the soft tissue or the piece of shell that has
been broken off, or the microwaved inner lining of the eggshell (a leathery
white tissue).
The epoxy is toxic until cured, so don’t let it touch anything but the snail’s shell
during the patching process or you will risk compromising the snail’s health, or even
killing it! Patching is best done as a two-person operation since the epoxy can’t touch the
snail’s soft tissue, and therefore your hands shouldn’t touch the snail’s soft tissue after
handling the putty. Once the putty is mixed and ready, you are ready to start patching:
Step 1: Make sure there is no debris or slime on the
exposed tissue. Trapping any foreign substances that may have
bacteria could lead to bad infection. If you are using eggshell or
eggshell lining to cover the holes, make sure it is microwaved so
that it is sterilized.
Step 2: Cover the exposed area with either the missing
piece of shell, a piece of eggshell, or a piece of the eggshell’s
inner lining that mostly covers the area (more than one piece can
be overlapped to cover an area for which the curvature of the
shell is too great to be covered effectively by a single piece of
eggshell).
Step 3: Take just enough putty to cover the area and mold
it with your hands to the vague shape of the part of the shell it
will be covering. Place the putty patch over the piece(s) of
shell/eggshell and gently press it into place. Smooth the edges
down gently so as not to create any further shell damage.
Step 4: If the damaged area does not wrap around the
spire, a thin layer of epoxy putty over the spire may be necessary
to hold the patch in place so that it doesn’t pop off at some point
in the future while the snail is in the tank.
After the patch is pressed into place such that it will stay on, leave the snail in a
deep bowl that it can’t fall out of if it decides to walk around (even a small fall could be
fatal as the weight of the patch would almost certainly cause the snail to fall spire-first).
The cure time of most marine epoxy putties is approximately one hour. The snail will be
fine out of water for that amount of time. If it decides to walk around, put a thin film of
water in the bottom of the container to keep it moist. Do not get the patch wet though,
Health Problems & Solutions – Donya Quick 11
because it needs to be dry to set properly! After the cure time
has passed, fill the bowl with water from the tank and let the
snail sit in it for a few minutes—this will help eliminate
possibility of releasing toxins into the tank. Dispose of the
water in the bowl, and put the snail back in its tank. It’s ok if
the patch smells faintly of plastic; as long as it cannot be
dented with a nail it is no longer toxic.
A successfully patched female ivory
apple snail. She returned to normal
activity immediately after patching
and began laying eggs again only a
week later.