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Comment on SF man selling jellyfish as household petsparent

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I'm not associated with the company in the story, but I'm a long-time aquarium hobbyist and had to create an account here just to comment on this.

Jellyfish are not active swimmers--they ride whatever current is in the water. In square tanks, this causes many species to get stuck in the corners where the water is stagnant.

Also, this means that they can't fight the current and generally get sucked into the filter intake. At the same time, they need strong current (see the comment about them getting stuck in stagnant areas) so you need a filter with a strong intake.

Some species, like moon jellies, all you need to do is diffuse the intake. You can see a section in the video where in the background they demonstrate a filter with the intake buried under a layer of marbles.

For other species, you need a specially-shaped tank called a 'kriesel'. (Do an image search for 'kriesel jellyfish' for some examples.) These tanks are shaped like a hockey puck standing on its edge, and move the water in a circle, so that no area is stagnant. Also, a water current blows across the filter intake, so the jellies get pushed aside instead of being sucked in.

Fun fact: The big jellyfish display tanks in Monterey Bay aquarium are actually oval-shaped kriesels with current blowing down both sides, and back up the center. That's why the jellies always seem to be upside-down--they're facing into the current in the center of the tank. :-)

I'd also disagree with the claim that jellies don't need any "exotic care": They're physically very fragile, and you have to be very careful to avoid damaging them when you clean the tank. They also require special food (notice that you're supposed to order special food from this guy) and high water quality, not to mention the special tanks already mentioned.

When I used to spend a lot of time at the Bellagio I frequented a sushi/hibachi grill restaurant called Shintaro that had a bunch of jellyfish tanks in the sushi bar area. They would alternate background lighting colors for aesthetics. It looked awesome, but when I asked them about maintenance they said, and I quote, "jellyfish very hard keep alive".

Great post. I don't understand why people have to trap animals like jellyfish and put them in prisons / tanks. Just let them live where they are meant to, the ocean.

To be fair jellyfish are about the least 'animal', animal you can have, it's a little like imprisoning a house plant.

To expound upon this, we have no reason to believe the jellyfish even knows what's going on, let alone cares. They don't even have a central nervous system- WORMS and FLEAS are more likely to have an opinion on the matter than a jellyfish.

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