RE: NANFA-- weird darter illness?

Nick Zarlinga (njz_at_clevelandmetroparks.com)
Mon, 13 Jan 2003 07:50:51 -0500

Sounds like you might have some kind of supersaturation of gasses happening
in your system. Any chance you have a pump on the system which is sucking
air through the intake? What happens in a situation like this is that the
air that gets entrailed in the intake of the pump gets "sucked" so hard that
it essentially gets dissolved into solution. This is especially prevelant
if there is some kind of pressure chamber after the pump, such as an ocean
clear filter or the like. The air that gets dissolved in the water passes
through the fishes gills and collects in the capillaries of the fish.
Usually it is most noticable in the fins but I have had it happen on the
skin at times also. Essentially, this is the same effect that SCUBA divers
get when they get the bends. It is the nitrogen that is actually the
culprit which comes out of solution (blood in this case). Sort of like
opening a pop can and having it effervesce. It is also more dangerous in
cold water than warm since cold water can hold more gasses. To alleviate
the problem, check all the intake lines of the pump and make sure that there
is no "whirlpool" effect and that all connections are secure. Also, never,
never, never...... have your effluent from a pump enter the tank under the
surface of the water. You need to have some surface aggitation to degas the
water. It is also good to run the water through a degassing chamber, such as
a trickle filter.

Nick Zarlinga
Aquarium Biologist
Cleveland Metroparks Zoo
216.661.6500 ext 4485

-----Original Message-----
From: owner-nanfa_at_aquaria.net On Behalf
Of geoff
Sent: Sunday, January 12, 2003 8:10 PM
To: nanfa_at_aquaria.net
Subject: NANFA-- weird darter illness?

A couple of weeks ago, I went collecting for stonerollers about 30 minutes
from my house. I found some, along with some nice orangethroat darters for
someone I promised colorful darters to. Its possible they are rainbows, but
I don't think so.

I have collected at this creek, but I've never taken anything home from that
creek before.

While we were collecting, I noticed a few dead minnows here and there in the
creek, which I attributed to some yahoo on an ATV - there were fresh tracks
in the creek.

Anyway, I have had these fish about 2 weeks and I have just started losing a
couple of them. I have kept them at about 50 degrees since collection.
They
have seemed to eat alright.

Tonight, while cleaning the tank, I noticed one male darter swimming very
badly. He was still rather vigorous, but he swam in very sharp circles.
pretty much like a pomeranian chasing its tail.
His colors were a bit washed out, but there were no obvious lesions on his
body. I think I saw a couple of clear bumps on his side. I killed him and
flushed the body.

I have never seen anything like this. ANyone have any ideas?

Geoff Kimber
Lexington,KY

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/ reflect the beliefs or goals of the North American Native Fishes
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/ nanfa_at_aquaria.net. To subscribe, unsubscribe, or get help, send the word
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/ nanfa-request_at_aquaria.net. For a digest version, send the command to
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/ For more information about NANFA, visit our web page, http://www.nanfa.org