h a l f b a k e r y"Bun is such a sad word, is it not?" -- Watt, "Waiting for Godot"
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This is such a lousy title for what I think is a good idea. I
just blanked on that part....
This idea builds on [8th of 7]s Hamster Wall-of-Death
Enclosure and [Maxwell Buchanan]s contributions to it,
Wall-of-Death Aquarium, which featured fish enclosed
in
a vertical cylinder. Neither
of these has much to do with
death, as it
turns out,
but it did give me inspiration for this idea.
I have been informed by respected biologists that fish
orient
themselves while underwater primarily to the direction of
incoming light. There are exceptions, but most fish swim
with their backs towards sunlight (up).
Correlation does not imply causation, as the maxim
goes.
In other words, just because fish swim upright, it does
not automatically prove that they do so in response to a
light source.
Thus, scientific experiments were undertaken upon fish in
tanks in which the light source was moved to the side, to
the bottom, etc. The lab fish altered their notion of
upright to sideways and even upside-down, in response.
SO, I propose a cylinder-shaped aquarium, say two feet in
diameter, and two feet long (or high, as the aquarium
rests
on one end, that is, as a vertical column. The aquarium-
column will have a smaller, hollow cylinder installed in
the
length of its longitudinal axis. A tube within a tube, if
you
will.
The inside surface of the outside glass--where the fish
swim--is a one-way mirror, transparent from the outside,
for observation and enjoyment.
A light source is installed in the center hollow tube. The
fish will perceive the inside wall of the outside tube as
the
bottom of the aquarium, the lighted inside tube as up
and therefore, swim sideways, bellies toward the viewer,
backs towards the light, providing amusement, education,
and happily confused fish.
It seems likely to me that fish respond to gravity as well
as
light. With this in mind, the entire tank assembly could
be
rotated on its axis, providing centripetal force, which
would
help counter the actual force of gravity, and maybe
confuse
the fish further.
How to confuse a fish.
http://www.med.nago...834/NJ580301071.pdf See section "Disorientaton of fish exposed to microgravity" [mouseposture, Oct 09 2010]
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Annotation:
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The light business.....I wonder. Does anyone happen to have
an aquarium, some fish, a dark room and a torch? |
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I was wondering this myself..and, as an after-thought,
why this wouldn't work on a regular rectangular
aquarium with all sides, save one on the side,
blacked out. Seems simple enough to try...and
intuitively unlikely to work. |
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Still, science says it works. I imagine it might take
awhile for the fish to get used to this arrangement
and not notice their feces dropping sideways, or
bubbles passing them horizontally. |
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This needs to be built. That is all. |
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Brilliant, [Boomer]! It would be fun to see them in a zero-gravity environment, too. Bun! [+] |
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Inside the San Francisco Aquarium is a large cylindrical tank. From distant memory, it's on the top floor and the circular space in the middle must be entered from below, meaning that once inside you have a 360 degree view of the surrounding water. |
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This water contains rapidly swimming barracuda fish, who orbit the tank, moving against a strong current. I recall a the tank being bathed in cool blue light, in an otherwise darkened room. For some time I was alone with these amazing fish. |
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I had a friend who worked there as an engineer, so he was able to take me in when the place was closed to the general public. |
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This walk-in version sounds delightful and could be
implemented. |
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The more I consider this concept, the more I doubt
the science of my own idea. It's so hard to imagine
fish orienting themselves to the light when they have
swim bladders that orient to gravity. I wish I had
more data on those experiments... |
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"When a fish is illuminated from the side, it tilts its body
vertically 20-30 degres so as to turn its back toward the
light source. This tilt response is called the 'dorsal light
reaction (DLR).'" (Note that the tilt is less than 90° i.e. the
gain of the reflex is less than 1.0) |
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However, "fish can maintain the upright
posture in darkness," so there must be other sensory
sources of information about the vertical as well. Not only
that but otolith-removed fish can accomplish this feat.
The <link>ed article speculates that "the swim bladder may
be a candidate graviceptor organ." Just as you said. |
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One of the best things about the HB is how it sends one
off to research topics one would otherwise never have
thought of. Who knew, for example, that fish-otoliths are
the subject of a huge literature having nothing to do with
their utility to the fish? |
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//One of the best things about the HB is how it
sends one off to research topics...// |
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Amen to that [mp]! Thanks for the link. I searched
too, but didn't think to include "confuse" in it, even
though I used the word in my description. |
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Btw, I've seen cod otoliths made into jewelry in
Alaska. |
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Cylindrical tanks with a hollow inner cylinder exist,
I've seen one and it was cool. I think they're for Angel
fish or Jellyfish. The hollow tube in the middle is for
water to overflow into. You then filter it and pump it
back in. It would be easy to put a strip light in the
tube. |
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If the outer wall was a one-way mirror, it would
reflect the inner light so it would be like 2 light
sources, so not ideal. |
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//If the outer wall was a one-way mirror, it would
reflect the inner light so it would be like 2 light
sources, so not ideal.// |
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I actually started on that problem in my original
description, but scrapped it, hoping no one would
think of it, fool that I am. Still, the reflecting
surface would not be as bright as the actual light
source. |
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It would be really cool if fish were perfectly light-
reponsive. Then you could flash the light source on
and off from different directions and the fish would
all flip together in response. |
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