[Papa Doug]

Do those of you running mechanical filtration in your sump, pick Cerith snails out of the floss before changing it? I change mine about twice/week and it always contains several Ceriths.

They seem to be all over the overflows, in the grate and such.

[Reefland]

We have Ceriths in our tank and they have never made their way into the overflow or down to the sump. On that note, none of our snails have.

[Poseidon]

Nope, they stay on the bottom in my tank too... I only have to dig out Astrea's... Darn things get STUCK in my CPR overflow because it is so narrow...

[Papa Doug]

It appears after some discussion on another board, that there are a couple of different kinds or imposters. Still trying to get to the bottom of it.

[Ninong]

Doug,

My Cerith snails are from Reeftopia in the Florida Keys and I am positive that they are one of the many different species of the genus Cerithium: Cerithium - Google Image Search You can see a picture of my Cerith snails on Reeftopia's website. Be sure to read their caption, too: Aquarium snail and crab photos from Reef Topia

My Cerith snails are mostly nocturnal. They will climb the walls of the tank at night to feed on algal film. They also like to feed on algae in the upper layer of the sand bed and along the glass at the interface of the sand bed and the tank wall. I have observed my Cerith snails laying egg strands in wavy spiral patterns on the glass walls of the tank at night.

All of my Nassarius snails came from Reeftopia, too. They are all supposed to be Nassarius vibex. It might be possible that a few Ilyanassa obsoleta were mixed in but I'm not suggesting that that actually happened because Ilyanassa obsoleta's range doesn't extend that far south. In any event, some of my Nassarius snails have gone over the corner overflow and down through my Stockman standpipe into the sump. I would say that I probably retrieve three or four of them per month from the sump. I have also found Cerith snails in my sump but not very often. I would say that I probably remove, on average, one Cerith snail per month from my sump.

The grate at the top of my overflow compartment is made of black eggcrate. That allows for greater water flow capacity compared to the combtooth grate but it also allows anything small enough to fit through the ~1/2" square openings to get through and into the corner overflow compartment. In the case of snails, they would then have to make their way up the standpipe and then through the submerged opening at the top of the pipe. When I experimented with lettuce sea slugs (Elysia crispata) during the first few months after my tank was set up, they went over the overflow continuously. I started out with four of them and I had to retrieve one or two from the sump every day -- sometimes twice a day.

[Papa Doug]

Thanks for the info George. Going to look at it. My overflows are 1/2in. eggcrate also.

[Nelsonius]

I have never had to pick out any snails from my filter. At least I've never noticed any in there. I have a ton of tiny snails that are pretty much nocturnal, but haven't see any in the floss. I don't know what king of snails they are, but they multiply like crazy.

[Papa Doug]

Interesting point in the article, with the pic of the smaller black ones. I must say, they do look like what I have.

[Ninong]

Originally Posted by Nelsonius

I have a ton of tiny snails that are pretty much nocturnal, but haven't see any in the floss. I don't know what king of snails they are, but they multiply like crazy.

Those are probably Collonista sp. trochids. I have hundreds of them in my 120-gal reef aquarium. They are very tiny (3-6mm) and rather attractive under a magnifying glass but they are a nuisance as far as I am concerned.

They are strictly nocturnal, coming out onto all exposed surfaces in the aquarium (rock, glass, etc.) around dusk and retiring to their hiding places well before dawn. They appear to be herbivores grazing on algal films. Unfortunately there are so many of them (several hundred) that they deny needed nutrition to other more desirable trochids in my tank. Their numbers seem to fluctuate between about 800 at the high end and 300 at the low end. They are impossible to completely remove because they are so small and because they are in every nook and cranny in the tank.

Dr. Ron Shimek discusses them in this article: http://reefkeeping.com/issues/2004-05/rs/index.htm

P.S. -- In my tank, they do go over the corner overflow and down into the sump where I remove at least a dozen or two every week. This seems to have no effect on their overall numbers. I have finally come to accept them in spite of the fact that their presence makes it impossible for me to add any new grazing snails to my tank.