Re: NANFA-- silverside survivers

geoff kimber (gkimber2_at_earthlink.net)
Sat, 14 Oct 2000 10:9:47 -0500

In may 1999 I was in amarillo Tx looking for red river pupfish. I went to
the Canadian river right below the dam for lake meredith. THere is a 5 to
10 acre lake that is heavily used for swimming. At this time of the year,
the water was mid- to upper 70's (I didn't meaure, but the kids liked it).

I scooped up a bunch of brook silversides with the seine and walked to the
shore. Since I didn't realize what they were at first, I didn't treat them
with any particular care, just pretty much how I handle any seine load of
fish. I scooped them out of the net by hand and put them into a 5 gallon
bucket with clear water from the lake.

Back in the car, I put the fish in a cooler with a powerhead plugged into a
power inverter.

During the 12-hour drive to tucson, I lost no silversides. When I got
home, I had 18 silversides which I put into a 55 gallon tank with the
pupfish. I lost 2 fish over the next couple of days and then they did
fine. I fed them flake food with occasional black worms. After a couple
of months I started losing 1 or 2 fish a week. Their normally translucent
bodies would get milky and they would die. I added a bunch of ocean salt
to the water and brought the salinity up to 1.018. The fish tolerated this
quite well and they stopped dying. After a couple of months, I began
changing the water with tap water. Once the salinity was back to normal,
the fish started dying again.

I don't know the water conditions in the Canadian river, but I can
speculate that the pH was pretty high. The tap water in tucson has a pH of
8.4 to 8.9 and is pretty hard.

So, what did I do to keep them from dying? I have no idea. I can tell you
that their noses were pretty bumped up in a tank as small as a 55. I think
they would need either a REALLY big tank or a good sized pond to breed.

I have read that brook silversides are widely introduced as a forage fish
for introduced game fish. I really have to wonder why fisheries biologists
can move this things so easily and we can't.

Geoff Kimber
Lexington, KY

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