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03-03-2010, 10:37 PM
Does anyone know a link to an article on major causes of fish stress?
Lighting in particular?If it has a category that is.

03-04-2010, 02:27 AM
Does anyone know a link to an article on major causes of fish stress?
Lighting in particular?If it has a category that is.

Heres a decent one:


Here is an awesome PDF you can download:

Excerpt on lighting:
Lighting, Turbidity, and Visual Stimuli
Many aquatic species, fish in particular, are affected by sudden changes in light and by
photoperiods. One facility, upon the installation of a 24-hour camera monitoring system,
inadvertently discovered their perch were traumatized when the overhead lights automatically
background image
clicked on or off. The fish would throw themselves violently around the tank in a wave of panic.
This stress was easily eliminated with the installation of a gradual, light-dimming system. The
lights came on and off slowly, replicating the natural effect of dawn and dusk.
Growth and reproduction cycles are also interdependent on light cycles in many aquatic species.
Animals housed under incorrect intensities or durations may develop either acute or chronic
problems in these areas.
Turbidity, the index of light absorption, is created by the amount of both particulate matter and
dissolved solids in the water. It is not necessarily an indication of poor water quality. Some
species, such as Xenopus, carp, catfish and tilapia, prefer a fair amount of turbidity. Others, like
salmonids, prefer much clearer water.
Some species are from environments with crevices, sand, or plant materials which are used to
conceal themselves. Xenopus laevis, crayfish, lobsters, clown fish, squid, and horseshoe crabs
are a few examples of species that prefer to hide. Bright, clear tanks with no concealment options
can be distressing. Just entering a room can send various species scrambling for cover,
occasionally injuring themselves or others in the process. While some animals will eventually
acclimate to visual stimuli, it is best to provide appropriate substrates and containers in which the
animals can hide.
Excess water movement can be a stress for some species. Xenopus leavis, for example, are
naturally found in very still, murky African deltas. An adult has approximately 180 lateral line
organs distributed over its head, neck and trunk which detect the friction of the water movement.8
This can be indicative of the frog's next meal (an insect's flutter on the water's surface, the wiggle
of a small fish) or it can alert the Xenopus to danger (the motion of a predator about to strike).
Xenopus will often face the current to remain vigilant. I have often heard people confuse this with
the animal "enjoying a water massage." Water movement is naturally a cause to react. Being on a
constant "state of alert" is a stress, not a day at the spa.
For other species, lack of water movement is a stress. Sea urchins, oysters, mussels, starfish,
and most marine invertebrates rely on powerful currents to bring food to and carry waste away
from them. Some fish (salmon, trout, etc.) also prefer a higher current, as would be found in the
swifter moving waters from which they originate.