Tuesday, June 16, 2009

Dishpan aquarium

It all started with the worm.

About six weeks ago, I came home with a half a worm in a bag of sand. When it was still alive a week later, I blogged about it. To recap: the worm was a sandworm ("Sandy"), Nephtys caeca, and among its characteristics is the ability to survive decapitation. It can regenerate a new head or tail; cut it in half, and you may get two worms. I decided to try to keep the worm alive, bringing home fresh sea water for it, to see it rebuild itself.

All went well, at first:

Sandy, four days after the blog post, showing new growth at the broken end.

A week later; four new segments! And the worm is starting to burrow.

Every time we went to the beach, I brought back a litre or two of salt water. Other things came along with it; I had the water, and a dishpan to house them in, and a little bit of biodiversity would make the place feel more like home. I brought home handfuls of seaweed, a few clams, rocks with mussels stuck to them, a few interesting snails. And every day, I poured off half the old water, and added an equal amount of clean, new seawater.

Unfortunately, that wasn't enough. One day, the water stunk. And my poor Sandy was dead. So were a couple of snails. I changed their water completely that day, but it was too late.

But I still had a dishpan half full of live things; I couldn't just quit. So I modified my routine. Now, every day, twice, as regularly as the tide, I pour off all the water, rinse out the sand to clean out remains of meals, etc., and refill the dishpan with fresh water. We don't get to the beach every day, and I can't carry all that water, so I filter the old water thoroughly, sloshing it plenty to aerate it, and ending up passing it through two layers of coffee filters.

A lot of work. I hadn't intended to have a seawater aquarium, and I don't have the equipment. I think I need to acquire a bubbler, a filter, a good pump. And maybe a gizmo for measuring salinity so I can make my own seawater.

It's been worth it, though. I've been watching my little world; it's fascinating! I keep discovering new residents or behaviours I never would have guessed. The seaweed comes full of its own residents, and each mussel or snail turned out to be carrying at least a few smaller snails and some barnacles.

I have some 30 photos that I absolutely must share. Here's the first batch:

A tiny white crab with a face on its back.

Barnacles on a snail shell, fanning for plankton.

I learned something about barnacles; each one is an individual. Each little net (feathery legs, or cirri) is cast differently than the neighbour's. Some spread out widely, others make a narrow spoon; some fan from the base, a few stick out a long stalk, then uncurl a little scoop at the end; the nets are triangular, a half-circle, or a full circle. And each one has its own rhythm. In general, the tinier the barnacle, the faster and more often it fans, until the very tiniest seem to be vibrating constantly. A big barnacle spreads its nets more slowly, and sometimes rests for a full minute.

Big barnacle, with algal "moustache".

Hermit crabs: I brought one home on purpose. The others hitchhiked in seaweed.

Big guy, with long, cool, dotted tentacles and ...

... stripy eyes.

Big guy meets another, this one with orange legs with white polka dots.

A tiny, homeless hermit, out searching for a shell. I donated a few empty ones I had on hand. Black claws, dark sunglasses.

This little critter threatens me from a bed of seaweed. Look at the size of that right claw!

A tiny hermit in a pretty brown shell, on a torn edge of kelp. His legs are white, the tentacles short.

Same one, on a mussel. Look at the mussel's lips! That goop is mussel feces; every so often he spits out another blob.

I learned something new about mussels, too. They move about. I always assumed they stayed rooted to the rocks, just like the barnacles do. Mostly, if the large ones have a good foothold, they just shift themselves, much as I stretch and turn in my chair to ease stiff muscles. But the littler mussels will wander all over, up and down the rocks, across the sand, up the sides of the dishpan.

That's enough for now. Tomorrow, I think, the anemones.



  1. Sounds like you're having fun (and also having a lot of work). I'd watch those mussels, though - if they die, it might not be obvious at first, and that can cause obvious problems. I'd say that a pump or something to keep the water circulating and aerated would be your first priority to get.

  2. Looks like that worm grew something more than just a couple of segments before it pegged out - it also grew a new hobby for you :)

    Having your own artificial tide pool must be fascinating, if an awful lot of work. I love how you describe the barnacles and their individuality - something you wouldn't notice from a casual glance in a rock pool. What a wonderful post!

  3. That's the danger with this sort of thing: you start with a simple dishpan of seawater, start making improvements - and next thing you know, you have a few thousand dollars of equipment to maintain a massive tank and no room left in the house.

    It's kind of like photography that way.

  4. Christopher; yes, that's at the top of my shopping list. The mussels - I check them daily; if I see them moving, or if they close up when I tap them, they're ok. When the time comes that one doesn't respond, I'll remove it.

    Bird; As if I needed new hobbies! But it is fun.

    Tim; Now combine aquaria and photography; I may have to consider extra sources of income.

  5. Anonymous11:13 pm

    This is so interesting. Love the little homeless hermit crab. Has he chosen any of the shells you put out?

  6. Huckleberry; Yes, I saw it today, wearing one of my offerings.

    Christopher; I went out and got a pump. Works nicely, and everything seems quite content with the constant current.

  7. We tried this when we were kids...bring home tide pool treasures, and watched them slowly fade away as smells percolated from their ice cream bucket. That was our first lesson in the importance of clean water for these critters.

  8. Wow, neat observation about the mussels moving about. I saw a documentary about starfish once, and their movements in time-lapse photography. It was fascinating and a bit creepy. So many things we assume are stationary, just because their time scale is different than ours.

  9. Garden Lily;
    I've been thinking about time-lapse photography. Not only the mussels, but the anemones; they move around more than I could have imagined.


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