It is difficult to know what causes our fish stress in circumstances when we
think we are doing everything right. I have seen rainbows exhibit this
fright or "flight" behaviour for long periods (years). Your post brings up
a good point I forgot to mention to John - that is the dither fish. As you
pointed out - when these fish are in with other "more confident"? fish they
behave normally - but on their own something happens and they exhibit this
classic flight response.
One thing I wonder when seeing a school of fish exhibiting this behaviour -
where is the dominant male. In the examples I have seen I can't recall
seeing one truly dominant fish. This would make sense if the typical
response is schooling as they all must look the same. But at any given time
is there a dominant fish??? Maybe a dominant fish is required for the fish
to exhibit a more secure response. Perhaps in cases like yours when the
fish have been removed from other fish that it takes a while for one fish to
express dominance over the "herd". I have noted that the dominant fish is
not necessarily the largest fish, and dominance of the school can be passed
around over a period of time even during the course of a day.
Regards,
Barry.
-----Original Message-----
From: Jim Priest <cat at lascruces.com>
To: rainbowfish at pcug.org.au <rainbowfish at pcug.org.au>
Date: Sunday, 2 November 1997 1:04
Subject: Re: [RML] Archer River Trifasciatas
>Good Morning...
>
>I have a nice little school of Lake Broadwater fluvitilis that do the
>same thing. The tank is 30 gallons (approx 110 L) and is moderately
>planted. They have been in this tank all to themselves now for about a
>month and a half. Previously, they shared a 75 gallon (280L) with some
>Pappin Cr. tris and Dalanies Cr. dubolayi. The swam freely with these
>other fish.
>
>I know these fish are stressed, but don't know why. They just hang low
>in the weeds and only swim about when it is time to eat, and then only
>long enough to grab a morsel and retreat to their hiding places.
>
>I have my lights on 12 hours a day. I was planning on buying them a
>peice of driftwood for added security...but who knows.
>
>Jim