Saturday, February 6, 2010


It has been a while since I posted a photo of our favorite fish tank...much has happened in our lives the last year which means it got a little neglected. I still changed the water but it was starting to look sad. So over the Holidays Diego and I decided to dedicate some time (and $$) to making the kitchen tank look beautiful again!
Diego and I built the canopy (the top part that holds the lights) and stand in 2005...our 1st carpentry project together! It took 2 weeks because the tank is 6 ft long and 2 feet wide (and 2 feet tall!), so it needed to be huge and well...we didn't know that a 2" x 4" is actually 1.75" x 3.5" so we had a few issues. Regardless, it turned out and now we have a beautiful stand and workstation...this is my workstation, so I am looking at this as I write! I love it! It makes me HAPPY! :)
This is our giant clam (Tridacna squamosa) which we have had for a year in another tank but decided it was high time for it to be front and centre (it is the size of a football!)! This is not your typical clam, most live in the sediment and filter particles out of the water for food. This one does filter particles BUT it also photosynthesizes like plants! Which means it needs light to survive! In it's beautiful mantle (the purple part) it hosts symbiotic algae cells. Symbiosis describes a relationship between 2 organisms where both organisms benefit and in this case the algae (called zooxanthella) provide sugar (product of photosynthesis and the basis of metabolism) to the clam in exchange for nitrogen and other nutrients the algae need to grow! Corals have the same relationship with the same type of algae and they too capture particles to supplement their diet. I think they are among the coolest things ever! (**Note: I say this A LOT when it comes to anything alive in the sea or on land...I LOVE the natural world and am fascinated by no matter how often I say it, I mean it!).

Here is a little tour of our tank. The blue fish you see perched at the beginning is a bicolour blenny, the only other fish we have are 2 clownfish and a Hippo Tang (that is very shy so is not in the video).

The other REALLY COOL thing we got recently was a rock that is covered with a species of hard coral called Porites that has Christmas tree worms, barnacles and (here it comes...) the COOLEST filter feeding crabs! Check out the video! (My apologies for the blurry parts...).

The crabs live in holes in the rock/coral and have modified antennae that look like combs that they sweep through the water to capture passing particles!!! They then take their "net" to their mouth and just clean it off and stick it back out to catch more! They are so CUTE! The video gets in nice and close to one of them. We have 4 living in our rock. Two that have spotted claws like the one in the video and the 2 others have stripes!
The Christmas tree worms, are tube building filter feeding worms. They come in many colours, on our rock we have blue, white and brown, and red ones. You cans see a blue one at the beginning of the video on the bottom right of the rock. You will see some blurry and not so blurry close ups of some of the worms. You can see that they have a spiral top that is wide at the base and tapers as it gets to the top. If you have seen Avatar, you have seen these as terrestrial plants that when touched retract into their tube. These "plants" in the movie look EXACTLY like these worms. Although, I was perplexed at what these "plants" fed on in air...the delicate feathery top of these worms is designed to capture small passing particles in the water, not in air. The entire surface of the feeding appendages (feathery top) are covered in tiny hairs called cilia (the same kind that line your lungs) that move the food down to the worms mouth at the centre of the base of the feathery top. They actually do retract very quickly into their tubes, like the plants in Avatar, to avoid being eaten by passing fish. They are actually light sensitive (as well as motion), so if a fish passes overheadand and casts a shadow they will retract.
Last but not least, the barnacles! You can see one feeding on the bottom left of the screen as the video zooms in on the crab. It too is a filter feeder...can you tell that there is lots of food in the water column in the ocean? So many organsms make a living capturing suspended particles from the water column! Barnacles are cool in that they are a crustacean, like the crabs, but they have built an outer shell that houses a little shrimp-like animal inside. The little barnacle lays on his back inside the shell and uses a modified arm that acts like a giant fan that they stick out to capture passing food. Also, relative to their body size, barnacles have been deemed the organisms that have the longest penis in the world! Why is this you ask? Well since they live attached to the bottom, their nearest neighbour could be quite a distance away (ie: a few centimeters) so to be able to reach them...they have a really long penis!

Although marine tanks are AMAZING, there are many sustainability issues that surround the industry. Suffice to say in this post that we only buy tank-bred or sustainably harvested fish, corals and other invertebrates. The majority of our corals were grown here in Halifax and our rocks handmade by a close friend. I will save the issues and more eco-friendly options for another post.

Well that's it for today! Have a great weekend!! :)


  1. haha i love that barnacles have the longest penis!!! awesome!

    also- i LOVE your tank as well, it is SO BEAUTIFUL. the best part, all the coolest things aren't the fish at all :)

  2. Lovely! I ADORE the Christmas tree worms! (I never thought I would hear myself say something quite like that...) Everything in your tanks is beautiful and fascinating. :)

  3. This is such a great post in so many ways, Alli!! I'm sending the teens in our biology class over to check it out (we dissected clams just the other day and this is a great lesson on some other underwater species).

    I also love your workspace (drooling with envy)! It's so peaceful and calming to watch things move/swim in an aquarium but I am far too lazy to try and maintain one. :}

  4. Beautiful tank, so colorful. You sure keep it nice and clean. Like Sherrie, I love the Christmas Tree worms.

  5. when i was doing some drawings of coral last summer, i learned about the symbiotic relationship with the zooxanthellae. it totally blew me away to think about it. i was even more astonished to learn about the coenosarc, connecting the individual polyps of the coral. really makes you ponder what it means to be an "individual."

    thanks for a lovely post.
    btw, i got behind on that handmade give away, but i have not forgotten!

  6. hi, i just bought some christmas tree worms without properly researching them first... i was told they are attached to a living porite coral and that if the coral dies so will the worm. I do not have sufficient lighting for the coral and was wondering if the worms will die? Or would it be best for me to return it to the fish store? thank you much

  7. Dear Anonymous,

    The likely reason that the worms die when the coral dies is because corals secrete nasty chemicals when they die. What usually happens is that the worms just vacate their homes and because they are so vulnerable without their tube they get eaten. It takes the worms a long time to rebuild a calcareous tube. Not all Christmas tree worms live with corals. I have some in another of my tanks attached solely to a rock. So if it is the worms you are looking for and not the pair, then I would return the coral and keep looking for just the worms.

  8. WOW! I don't know what else to say except that your posts on this subject near and dear to your heart are so fascinating.

    Thanks for exposing us to this very interesting information.