Erratic Fish Bahaviour

Question
I have an Oscar fish that displays erratic behaviour when I turn on the light. The Oscar fish is about 6' long and is in a tank 108cmL x 38cmW x 40cmH with two filters, one internal and the other waterfall. We also have a 5' Redclaw (crayfish) in with him.

This light isn't an aquarium fluorescent light but just a normal florescent light, however, has the same wattage as aquarium lights (36W). When I turn on the light he seems like he's panicking and begins to swim in circles, like he's disorientated. When we turn it off he stops. Also, he stops panicking when we put food into the tank, he eats it, then starts again. At first,  I thought he was just doing it to get attention to be fed.

Before hand we had a much smaller, dimmer light that emitted a glow, maybe he's either afraid of this new brighter light or excited because he can see?

Another thing is, we recently (9/01/08) cleaned and changed the bottom of the tank from small stones to tropical sand. Maybe he's still distressed from that?? But whatever it is he doesn't seem to be very happy with it.

Sorry for the rather long Question.
Thanks
Adam

Answer
Hi Adam,
  Bright light is alarming to many fish.  When you turn on the light, are there already other lights on in the room, or does his world go from black to lit with the flick of a switch? It it does, then his behavior is perfectly normal.  The solution is to have some other light in the room (maybe a little night light) so that he doesn't get blasted by a lot of light all at once.

-- Ron
  rcoleman@cichlidresearch.com
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