hitch hiker needs identity...

[eevenson]

Just found this little guy in my aquarium. Is it anything to be concerned about? If you know what it is, please tell. He looks like a small black/grey snail or slug.
Thanks in advance

[Samper]

Does it have a shell?

[eevenson]

No,does not look like it-have not really got a close look at him.

[Ninong]

Pick it up and put it in a small glass or cup -- something made of clear glass so that you can get a good look at it from both the top and the bottom. Put some of the tankwater in the glass. See if it looks like this or this. If so, put it back in the tank.

[eevenson]

definately the first link. So i take it he is ok?
Thanks for the quick responses, you guys rock!

[Ninong]

Yes, he's OK. His name is Stomatella varia.

[Ninong]

I should probably point out that both pics that I linked were of the same creature: Stomatella varia. And it does have a shell but the shell is not all that noticeable and it doesn't cover all of the snail. They're called "cap snails." They're beneficial grazers.

I find them much easier to identify from underneath because that's the way I usually see them on the glass of the tank and they're very distinctive from that angle.

[Ninong]

Here's another link for you to check out. That one includes a view of the snail from underneath. (There is a typo on that page that I just linked. It should read "Mollusca," not "Mullusca.")

There is considerable variation in the appearance of this species (which is how they got the name varia) but they all look somewhat like that. Some people call them cap snails and some people call them bubble snails. They're a very primitive trochoidean.

You need at least one of each sex in order to have them reproduce in your tank. You might have some more that you haven't seen yet. They're mostly nocturnal. These are broadcast spawners. Usually the male will release sperm into the water and then a nearby female will release a mass of eggs in a jelly mass. The eggs are fertilized by the sperm and then several hours later the embryos swim off as non-feeding larvae. Settlement out of the water onto a substrate will occur in about a week. A few of the juveniles will usually survive in a typical reef aquarium but hermit crabs and shrimp are predators, so your chances are better if you don't have any hermits or shrimp in your tank.