Maxima & Cmall white snails (cone like)

[JoeMack]

I was using my cool red cool cathodes mounted in my canopy last night and I saw 2 little white snails that were cone in shaked. They were maybe 3mm at the most. They really looked like a grain of rice if I was to say that they looked like something. They were on my maxima on the front side right next to the tissue. I have never seen these snails before. I will get a pic tonight if no one knows about these guys. I removed them because I would water be safe than sorry. Thanks.

[rshimek]

Hi,

They were likely pyramidellids. These are blood-sucking parasites of the clams. Here is some information about them.

Names: Pyramidellidae; Pyram snails, Tathrella species

The parasitic rice-grain snails are the bane of aquarists who wish to keep Tridacna. As their name implies they are about the size, shape, and color of rice grains. They are high spired snails with a translucent glassy, almost colorless shell, with a total length of about five millimeters. The shell aperture is oval, rounded, or broadly "tear-drop" shaped. There are one to three small folds in calcareous wall of the aperture on the body side, however these may be very difficult to see. There is no spout or siphonal canal. The animal's flesh is white giving the shell of the living animals a white cast.

These are opisthobranch snails more closely related to nudibranchs than to the major group of marine shelled snails. Unlike many of the opisthobranchs, however, the pyrams have a shell throughout their lives.

They do not have the rasping organ or radula characteristic of most snails, but they have a long proboscis with a pumping apparatus at the base. They are ectoparasitic and suck the blood and tissue fluids of their host. They use their proboscis to force an opening into their host's tissues and remain attached sucking blood. They may be found around any exposed surface of the host, such as the edge of the mantle, the byssal region, and possibly even down inside the host.

Commonly referred to as a Tathrella species in the aquarium hobby literature, it is likely that there are several species involved, and possibly even several genera. The taxonomy of this group is difficult, chaotic, and serious of revision. It is simply better to refer to these as "small pyramidellids" rather than to give the false precision of an imprecise name.

All opisthobranchs are hermaphroditic, so any two individuals may mate and produce viable offspring. Depending on the species, the eggs are brooded or deposited on the substrate (often on the host, or another snail). The juveniles hatch from the egg masses in a few days and grow rapidly to sexual maturity. Starting from one pair, enormous numbers of snails may be found within a few weeks to months.

In natural situations, most of the young disperse away from the host or predators eat them. Generally any wild clam will have a few of the parasites, and this is really no problem. However in the altered environment of a reef aquarium, predation pressures on the pyrams may be non-existent, and there is no place to disperse to. Under situations such as this, the parasite populations rapidly assume plague proportions. High populations of the snails may often kill tridacnid.

Removing the snails is the only sure cure, and this may be very difficult, as the snails are hard to see. There is no real cure other than continued diligence and removal of observed snails. Some fishes such as six-lined wrasses are said to eat the snails, but using them to remove these snails is by no means certain.

Here is a highly magnified image of one (this one was found on an Astraea, but looks quite similar to those found on Tridacna.

http://reefcentral.com/gallery/data/500/41Pyram_from_Astraea-med.jpg

[JoeMack]

http://www.southsko.com/reef/clamsnail.jpg
Looks like it. Very small. The for the TONS of info

[JoeMack]

"As their name implies they are about the size, shape, and color of rice grains."

I guess I described it pretty good :)

[manderx]

here's a pic i took of 2 kinds i have had in my tank. the one on the left was pulled off a clam, and the one on the right was pulled off a snail.


http://www.foresters-inc.com/mander/p_snails.jpg

[JoeMack]

Nice shot!

[fussoverthis]

Dr. Ron,
Hi, sorry to be bringing this thread up from so long ago, but I have a question in relation to this.

I always thought the tiny snails on the undersides of my astraea shells were young cerith snails. Now I know better. My question is: If I remove all astraea snails from the tank, will the pyramid snails starve and die off? I have no clams right now. Other snails I have are: ceriths, nassarius, mexican turbo, stomatella, bumblebee, and strombus (two species).

Thanks,
Melissa

[rshimek]

Hi Melissa,

Yes, if you remove the hosts, the parasites will starve. However, in your tank, the turbos may also be hosts, so I suggest you remove those as well.

[fussoverthis]

Dr. Ron,
Great! Thanks. How long do you think I should leave the turbos and astraea snails out of the tank before it is safe to re-introduce them?

Melissa

[rshimek]

Hi,

Hard telling, 3 to 4 months should do it, though.