NANFA-- fish wintering/feeding
Fri, 12 Dec 2003 14:07:37 EST

I have YOY dollar & pumpkinseed sunfish, golden topminnows, pygmy sunfish,
tadpole madtoms, and gambusia that I am overwintering in my "old house". The
"old house" remains unheated throughout the winter and temperatures have been
held at 50F for the last several weeks after being in the low 40's for several
weeks prior to that.

I've been surprised at their willingness to feed when the water temps were in
the low 40's. The gambusia and madtoms, surprisingly, fed actively at all
times - this especially surprised me on the gambusia as I thought they were
mostly southern, warm water fish?

The dollar, pumpkinseed & pygmy sunfish would feed, but certainly not
voraciously nor consistently. I feed live food only, and the food consisted of
daphnia, small gammarus and midge larvae. The sunfish often would hit whatever
live food was introduced into their tank without actually eating anything. Also,
they didn't seem to want to travel very far to try to feed. There were
obvious signs of slowed metabolism with them, but they do feed enough to look kind
of "fat" all of the time and there were usually no signs of live food within a
couple of days after feeding. I'm guessing they are less active & eat less,
but it takes longer for digestion. The golden topminnows refused to eat unless
the temps were over 50F and even then they weren't very enthusiastic about it.
Of the fish I have, only my Heterandria formosa appear to be more adversely
affected by cold temperatures than golden topminnows. I now keep the
H.formosa only in heated aquariums as they just waste away in colder waters.

Has anyone else had similar experiences? I've been surprised at how much
food my fish have consumed during the period of cold temps. As an avid
fisherman, I've always assummed that sunfish pretty much hibernate when water temps get
into the low 50's, maybe not?

Bruce Scott
Meridian, Idaho
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