NANFA-L-- Tiny limpets(?)-in-water line / snails & crayfish

Jase Roberts (
Thu, 01 Dec 2005 00:28:31 -0500


In one of my native tanks (north-central Vermont) I started seeing tiny snail-like critters right about-in-the water line. These guys are really small -- from less than 1mm long to maybe 2mm long now (definitely growing somewhat). I can't make out too many details with a 10x hand lens, but I can see that they've got snail-like mouths and probably antennae. What I can see of the shells looks a lot more like a limpet than a normal snail. They look to be roughly conical and fit tightly to the sides (I can push the critters around with a toothpick and they stay suctioned to the glass). The top set of pics-in-the bottom of looks about right, although mine are way smaller. There are probably 15 or so visible in my 10 gallon now, all right-in-the water line.

Do folks have experience with freshwater limpets? Are they common thing to have living in native aquaria? Any chance this is actually a life stage of a more conventional snail (I did have some in snails in this tank earlier)? I'm surprised that there doesn't seem to be anything in the NANFA e-mail archive mentioning limpets.

Second, I'm wondering about folks' experiences with crayfish/snail interactions. I had 6 or so smallish snails in my 30 gallon tank that disappeared within a week (only one large ram's horn snail remains). At the time I blamed my pumpkinseed, but now I wonder if the crayfish I had was actually the guilty party? I see some references to crayfish eating snails elsewhere on the Internet. Is it possible to have snails and crayfish co-exist in a tank, or will crayfish eventually wipe the snails out? I feel like I need some snails to control algae growth.

I also suspect my crayfish to be the culprit in cutting free the Coontail/Hornwort (Ceratophyllum) plants I have tied to rocks-in-the bottom. The plants are doing great in my 10 gallon tank without crayfish, but most were floating free and stuck to the filter within a week or two in the 30 gallon where the crayfish lives. Again, do other folks have experience with this? Solutions to keep the plants in place? Sorry, no idea on the species of the crayfish.

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