Fun tip - take your hand and wave it over the top of the clam. This should trigger a response in the clam. If it does in a quick manner, then it's in good health. If not, move onto the next.
Keep an eye out for pyramid snails on the shells as well. These will burrow into the clam and ultimately end up bringing it to its demise.
Lastly, you want to keep an eye out for a condition known as "pinched mantle." Imagine the mantle of the clam folded over itself, kind of like the pinches on the top of a dumpling.
I dont know if the LFS personnel will do the swish and would never allow customer hands in a tank though.
I wouldnt buy one without rolling it around and being able to look for snails myself. Clams are hardy enough to be out of the water for a while. If LFS doesnt want your hands in the tank, ask them to pass it to you.
Also, know what type of clam it is and if it wants to be / should be attached to something via byssal threads. A damaged byssal is usually doom for a clam (see above, pinched mantle, as a visual cue). Where I'm going is that some species of healthy & happy clams will want to be tied to something. If they're not, that's odd. If they are, the two items need to be handled as one or damage may occur.
Lastly, everytime I bring a clam home I run it under freshwater (kitchen sink, no joke) upside down and scrub with a toothbrush just to remove any loose bits of bad stuff.
Note also, clams like (in my experience at least) whiter light, like 10k, than the 20k many LFS have running. This'll mean their colors darken up, and also they slowly can be starved a bit. If you get a clam who's been under blue light, be slow & gentle about acclimating them to your tank and lighting.
thank you for the information. I appreciate it.In my experience if it doesn’t have a foot, it dies. My advice, is look for the foot underneath it’s shell. It’s more like an anchor than a foot but you will know what I’m talking about when you see it. I also agree with others about waving your hand over it
I have, it’s a good practice in general as long as you don’t drag it out too long. I’ve found clams to be much more forgiving of water changes than almost anything else. I mean, you see them in places in nature that go brackish when it rains! However, acclimation is definitely recommended, esp for temp.So do you do drip acclimation as well?
thank you for the knowledge. happy reefingI have, it’s a good practice in general as long as you don’t drag it out too long. I’ve found clams to be much more forgiving of water changes than almost anything else. I mean, you see them in places in nature that go brackish when it rains! However, acclimation is definitely recommended, esp for temp.
Great info all. Having lost half my fish to a velvet outbreak that started from a random petco invert (long story but petco- never again) I wonder if theres any way to make sure clams come in to the tank without any diseases/pests...
Given what @techdef said it seems like a freshwater dip wouldnt hurt?