High flyer

The ocean surface temperature along the east coast of Vancouver Island varies from about 6.5 degrees Celsius in February to a maximum of approximately 13.5 in August, our hottest month. (That's 45 Fahrenheit to 55 F.) My aquarium sits in a warmish room, with an average temperature of 20 to 21 degrees Celsius in the winter, more in summer. It's too hot for my intertidal invertebrates here, even in midwinter.

I keep everybody happy and healthy by adding ice to the tank. I freeze tank water in yogurt containers that have never seen detergent (which will poison some of the animals) and exchange them for the ones floating at the top of the tank several times a day. It's not pretty, but it works.

This morning, when I went to change the ice, I found a naked hermit riding the yogurt container. How he got up there, I don't know; he can't swim.

Hairy hermit, freshly molted.

When hermit crabs molt, they have to leave their shell. Often it won't fit any more when the molt is finished; all their growing happens in those few minutes between a molt and the hardening of their new skin.

They're vulnerable in this situation. Crabs aim for that juicy, curly abdomen. Fish, too. Luckily, there are no fish in this tank, but there's one big, starving (to hear her tell it) green shore crab. So the hermits head for the highest spot they can find to wait out the growing time. This one somehow found his way onto the iceberg.

It was a good choice. He'd already been damaged; he's missing his main defensive weapon, the large pincer on his right side. He uses the smaller one on the left to manipulate his food.

To replace the ice, then, I removed the yogurt container carefully, hermit and all. I put him into a bowl with a few empty shells for him to choose between whenever he was ready. 5 minutes later, he was dressed and rarin' to go. He had probably been waiting on the floating container for some time, not knowing how to get off without risking dropping into the waiting crab pincers.

With a good shell (according to him: he chose a broken one, well worn and covered with algae. He knows what feels best.) he went safely back into the tank.

(Look back at the photo. Look at the first foot on the upper left. It's not usually apparent that the legs are basically transparent, but here you can see the design on the yogurt container showing through.)

The tank and all

It's not a pretty sight.

I've been asked, several times, to post photos of my entire tank and setup, so here they are, with some notes on contents and operation.

Once upon a time, I got a book on tank decoration and studied it carefully. Unfortunately, my critters can't read. And they have their own standards of what's proper, besides. Anything I arrange, they manage to undo overnight. The hermits swing on the eelgrass, bear it down to the sand. The crabs overturn shells and rocks and uproot the vegetation. Worms collect things and glue them together in knots.

So I've aimed, instead, at comfort; what makes my critters happy? And like children with a room full of toys, all on the floor, they like a mess.

The tank as it was a week ago. A Mother Hubbard week.

(Warning: long post. Details, details. If they'll bore you, scroll down to the bottom before you leave.)

I fill the tank with eelgrass, and the hermits swarm all over it for a few days, until they reduce it to half the amount. Then they gradually eat away at it until there are only a few blades left and I go back to the beach for more.

The tank is a small one, approximately 20 inches by 10 by 2 high. It holds 10 gallons of water, full to the top. (Which I never do, because the snails like a patch of bare wall to sleep on.)

I loaded it with eelgrass last week. Yesterday, I changed the water again (I do this weekly) and re-planted what remains of the eelgrass. I should have taken a photo then, but I was tired and put it off. In the morning, the eelgrass had all been plastered down to the bottom.

As it was this afternoon. I see they've knocked the abalone shell on its back. A crab's doing, probably.

I numbered some of the contents to identify them for you.

Numbers in red. You may want to click on this for a full-size view.

• #1 is an abalone shell that has been in the tank since the beginning. All my critters love it, for climbing, for sitting, for hiding under the lip, or for privacy, burrowing down behind it. It looks bare in the photo, but there's a green shore crab under the lip, a family of anemones on the floor, one on top, and a few hermits wandering about. The mottled starfish is sleeping on the back.
• #2; A clamshell loaded with barnacles that I brought back for the leafy hornmouth snail. Most of the barnacles have been eaten, but the other critters love the empty barnacle cases, so I've left it to them.
• #3: You can't see it, but a purple sand dollar buried himself here last night.
• #4: A stone with barnacles. The starfish eat these, too. When it's done, I'll remove it.
• #5: The pump/filter intake.
• #6: The pump output, always making bubbles.
• #7: Red bladed algae. It was a small leaf or two growing on a clamshell when I brought it home, and it keeps growing and growing. I've pruned it several times. Everybody climbs through this; hermits, snails, crabs, anemones, assorted worms, the shrimp (taking their colour from it.)
• #8: One of the shrimp, in the background.
• #9: That annoying white crab.
• #10: (Back up on the left) The air pump intake. The bubbler is hidden behind the abalone, making the secret cave behind it even more interesting to the animals that live back there.
• #11:(On the right again) You can barely see a hint of the big burrowing anemone back here. Whenever I move her to a more visible spot, she moves right back.
• #12: Eelgrass, all plastered down.
• #13: The last shred of green sea lettuce. I haven't found any on the beach for a while. Mostly the crabs and a few of the worms eat this.

All the rocks and shells and greenery change position constantly, and are removed as they wear out or rot away. The only permanent part of the whole shebang are the pump, the air bubbler, and the abalone shell.

Now: the whole setup, as it is today, warts and all:

Yes, that's a Van Gogh print. Just because.

I've had the tank in various locations, but finally moved it to the kitchen counter to be near the fridge and water. It would be nice to have a separate space for it; a laundry room or garage, but that's not in the cards. So here it is; it works for me and the critters.

Around it are the lights; a 100-watt spot overhead, moveable. LED lights on the side and overhead. An LED gooseneck lamp for highlighting what needs to be seen. There's a flashlight in the cupboard above, for midnight checks. The rest of the lights are on timers.

While the hot weather lasts, I keep a fan on all the time, to help keep things cool. (That's also the reason I don't use normal fish-tank lights; they're too close, and they shut in the heat.)

Behind the fan are a couple of little pots holding tools: an eyedropper, tweezers, toothbrushes, paintbrush (for catching delicate tinies), a thermometer.

Behind everything is a big mirror, mostly to hide the tangle of wires, and also to add some backup light. It always gets spattered with salt blow-back from the pump.

The air pump is in the cupboard overhead. So are all the containers, food, microscope, trays, salinity meters, etc.

And the plastic container on the right contains two whelks and a big flatworm that came home hidden in the eelgrass or a clamshell. They are all hungry hunters, and too good at what they do. They're going home to the beach with me on the next trip. I've given them a few barnacles for meanwhile.

These are all intertidal invertebrates, and they like it cool. In this weather, and inside a house, that is difficult to manage. I keep the bottom shelf of the freezer full of containers of water. Several times a day, I put one in the tank, remove an equal amount of water, and replace it in the freezer. It works, and is less intrusive and 'way less expensive than the commercial aquarium coolers, if more time-consuming.

Periodic iceberg.

Water currents mingling; thawing saltwater ice, with warmer water.

So that's that. Any questions?