Mobiles anchored at the base instead of the top, with little glass or lucite bubbles at the ends of the arms. Those antique glass floats they sell in the quainter coastal regions would probably be ideal, if a bit big for the average household fishtank.

(Inspired, of course, by UB's idea of the same name.)
-- DrCurry, Sep 23 2002

Upside-Down Mobile http://www.halfbake...pside-Down_20Mobile
And outside the tank, for the silverfish. [FarmerJohn, Sep 23 2002]

So in effect - 'Fishtank Blimps'?
-- Jinbish, Sep 23 2002


what makes the mobile move? the fish swimming? then they stop still, rapt with attention and the thing stops. fish lose concentration. "why did I stop swimming?" fish starts to swim again. cycle repeats, again and again, incessantly = result = stark staring mad fish. this is cruel and I expect better from you Curry.
-- po, Sep 23 2002


Um, po, the mobile will respond to the water currents the way a regular mobile responds to air currents. I don't think the fish will pay much attention. It's certainly no crueler than sticking the fish in the tank in the first place.
-- DrCurry, Sep 24 2002


Inject a little microchip tag transceiver thingy into the fish in question. Then set up some sensors around the tank to triangulate his position. Mount tank on robot and tie the fish's swimming direction to the robot's directional input. Also, the 'bot should have a passive lead mode, so you can take your fish for a walk.
-- RayfordSteele, Sep 26 2002


RS: you sure you're in the right idea?
-- DrCurry, Sep 26 2002



random, halfbakery