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Trojan Bivalves and Killer Snails?

Jan 27, 2005
Hello everyone and thanks for your help about my water quality/temperature questions, I'm grateful as I'm new to marine.

Also glad to hear TONMOCON went so well, and jealous of eveyone who went. I got a tour of MBARI a couple years ago with my UCLA Marine bio professor, and I remember someone who worked there discussing the live vampyroteuthis they used to house there for observation, really incredible stuff. Have spent hours watching the Sepia officionalis at the Monterey aquarium too, it's what really got me interested in them.

I have a question about bioload and bivalves. The other day I bought some "green mushroom" cnidarians for my cuttle tank. After I put the rock in I noticed the cuttle kind of reacted to it - looking at it and even nudging it. The more I looked at the rock, the more it became apparent that it wasn't really a rock. It was a big clamlike creature encrusted with living things. It's bigger than the cuttle!

My concern it about how much waste bivalves produce. I thought that as a filter feeder it might actually help filter out proteins and waste. Giant clams can even consume more nitrogenous waste than they make, but this isn't tridachna, it's something unidentified. If it's going to be a toxic waste factory I don't want it polluting the tank.

The second question is about cone shells. There's a real little one that came in with the live rock. I like it, it makes a beeline for any uneaten crab parts and gnaws on 'em. But when it gets bigger could it be a threat to the cuttle?
Your tank sounds full of neat stuff! Gilly had lots of cone snails in his lab, with the important "do not touch" signs everywhere, with "in case of emergency, call Gilly." Be extra careful! They were separate from the cuttle, for what that's worth.

I don't know anything, I just couldn't resist your subject line. The experts will be with you shortly....

Depends on the cone snail. If its a fish eater I'd remove it. They have much wider apertures than the other cones (wear HEAVY gloves if you're planning on picking it up tho' just in case!) As for the clam I'd keep an eye on your tank parameters, it may be OK.


Worst thing about clams and other bivalves in the tank is that if they die it makes a big mess pretty quick! At least Tridacna can be kept by using high powered lighting and a supply of nitrogenous waste but many others are trickier due to the filter feeding habits.

Cool animal to get but I'd be a bit wary about it
Don't have a digital camera right now, but I will borrow one. They are definitely carnivorous snails, and race over to that leftover crab. The cuttle seems a bit stressed, I don't really need to test to know the water quality's gone down, I just need to do a water change and probably get rid of the bivalve. Actually the cuttle's behaviour is a pretty good indicator of water quality.

Other life in the tank now includes: rampantly growing macro-algae, pyramid snails, feather duster worms, brittle stars, bristle worms, a large swarm of amphipods, lots of tiny burrowing worms, filter-feeding crabs and other crabs, assorted little cnidarians (green and orange polyps, some brown anemone-lookin' things), a mystery thing in a hole that ejects a "geyser" of debris, and a miniature version of "Sarlaac's Pit" from Return of the Jedi - I dunno what it is, but it's very long thin tentacles cast over everything in a 5 inch radius, pulling in leftover crab bits. This whole community depends upon the messy eating habits of the cuttle!

I'm a little concerned about the sudden diversity in terms of molluscs as vectors for bacteria and parasites.
But they may not be a cone snail. Nassarius (sp?) look and act similar, but make a great addition to a cleaner crew because they do race to leftovers.

What colors are the tentacles of the sarlacc? :biggrin2:
Actually, I think I've got both. But the shell shape looks quite different between cone shells and Nassarius, and the ONE cone shell has that classic textile pattern (looks like little overlapping triangles) and the long straight abruptly truncated shell shape - something like this:


Can I include a link this way?

As for the sarlac's, the tentacles are whitish-transparent. I thought it might be some kind of tentacled worm, I remember something from my Invertebrate Biology class. Shoots up little mucous geysers, ew.
It has that pattern, but not all over like that. Could be another species. Anyway I'll never try and hand-feed it, or give it a friendly pet.

My tank's just had a massive algae bloom on the glass today while I was out. It got hot today, there's that big clam thing, and I think the cuttle found several hidden crabs and terminated them, maybe that's why. I've done a water change and changed the carbon, now I've got to do something with the bivalve. It's funny, some critters LIKE the nutrient overload - the barnacles have lots of micro-life to eat and get very active. When the water quality's normal the barnacles are not that active.

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