Terrible Advice Tuesdays: Your Bivalve Friends Need Some Supplemental Calories


Terrible Advice Tuesdays: Clams need to be spot fed regularly in order to thrive.

The Rest of The Story: Here’s one myth that just won’t go away, but really needs to.

Just like your corals giant clams (tridacnids – the ones we keep in our tanks) host of zooxanthellae. Several studies (Klumpp & Griffiths 1994 and Klumpp & Lucas 1994) confirmed that with sufficient lighting the zooxanthellae in the clam can provide all that a tridacnid needs. These studies also confirmed that “under good conditions, the zooxanthellae can typically supply a host clam of any size with an excess of carbon and energy”.

Furthermore, James W. Fatherree, an expert on giant clams explained how clams can filter feed fish waste, uneaten fish food and other organic material in your tank’s water column. This filter feeding serves to provide the clam with even more nutrients.

Several years ago I ran into James at a conference and I asked him what his take was on feeding clams. His advice was direct – clams do not need to be fed regardless of their size.  He suggested only feeding a clam if it is in a tank with zero fish for an extended (months on end) period of time.

Even I have made the mistake of believing that clams need to be fed and if you run into someone suggesting that advice, please share this post with them to set the record straight.

Works cited: Aquarium Invertebrates: Tridacnid Clams (Usually) Don’t Need to Be Fed in Aquaria, James W. Fatherree, M.Sc.

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Comments for this article (6)

  • Thats why theyre called filter feeders lol thats like putting extra food for your cleanup crews. I stopped spot feeding most things in my tank.

  • Jason Reynolds says:

    Thanks Mark!! This is a very helpful tip!!!!!

  • Scott Sanders says:

    That’s how I accidentally trashed my tank. I got my first clam and the LFS gave me a feeding supplements and my nitrates shot up to 64 from under 10 and my phosphate went through the roof. I lost a bunch of stuff and am still recovering. Have NO3 down to 3 and phosphate to .02 but still have a ton of the algaes and stuff around. Never again try to feed clams or corals.

  • Eric R says:

    Thank you Mark for the insight. You do your research and tell it like it is. Straight shooter and why I enjoy reading your materials.

  • Sal says:

    Thanks Mark , Thanks for all your advice I didn’t know I wasn’t supposed to feed my reef I am just getting started with the reef tank still have a lot of research to do.. Thanks

  • David Drucker says:

    My own experience with corals and clams tells me the same thing. Feed the fish, skim the water and lets the clams and corals claim the rest. So why do we keep reading articles on how much more rapidly corals grow when fed?

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