10 December 2007


Surfing molluscs

Snail at Flickr.comWe have aquatic snails in our fish tank, rather by accident. They came in on one of the plants we bought for the aquarium, and they multiply like crazy.

As someone who specialized in marine invertebrates for my biology degree, I rather like these little molluscs. They keep the sides of the tank spotlessly clean. They move surprisingly quickly (for snails). There are, however, often too many of them—they outnumber the fish by at least an order of magnitude—so we occasionally have to scoop some out and, uh, send them to greener pastures. (I have no doubt that things are greener, not to mention sludgier, in the Greater Vancouver sewer system.)

The snails perform one stunt that I hadn't seen before. Often they will make their way to the top of the aquarium and then "surf" upside down on the underside of the water's surface, riding the currents created by the tank filter. Sometimes one will circulate around for several minutes, its muscular foot flat against the surface tension, then it will either stick to a side or drift down to the gravel at the bottom to start trucking its way around again.

It's pretty cool, and probably the fastest these creatures will ever travel in their lives. Unless they get to visit the sewer someday, I guess.

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18 September 2007


New fish

The new fish at Flickr.comLast year we had a sad attempt at raising a single fish in an aquarium. He didn't last long.

This week, my wife and kids took it much more seriously and prepped a nice tank that now has five tetras in it. They seem quite happy, with live plants and colourful gravel, as well as a quiet high-tech filter that is keeping the water beautifully clear.

I'm quite enjoying the burbling sound and spending time watching the little tropical lake fish swimming around. The girls check on them regularly and feed them morning and night. I think we'll get some more fish soon. It's certainly a lot easier than a dog.

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