Anesthesia for fry?

s060965 at AIX1.UOTTAWA.CA s060965 at AIX1.UOTTAWA.CA
Wed May 29 23:53:36 EST 1996

 An anesthetic I used to use for zebrafish was 2-phenoxyethanol.  It is 
widely used in the aquaculture industry for trout and salmon.  I can't 
remember the concentrations used(but in practise it was more like 2-3 
drops in 300ml H2O).  It worked very effectively, with a low frequency
 of overdose.  I could find out the dose if you wanted to try it.

Cris Martin

On 29 May 1996, Herwig Baier wrote:

> Chi-Bin, the protocol you mention (from the Zebrafish Book) works nicely
> under most conditions. However, I found that under the fluorescence
> microscope the tricaine anesthesia is not deep enough: The larvae "wake up"
> and twitch, probably because of the light-induced heating. One can, of
> course, increase the tricaine concentration to 0.5mg/ml. This keeps the
> larvae still, but also mostly kills them (at least in my hands).
> Has anybody observed the same thing (and solved the problem)? Have other
> anesthetics been tried (like urethane)?
> --Herwig
> >Yiing Lin asked:
> >
> >>I was wondering if anyone has worked out any protocol for anesthetizing
> >>zfish fry and bringing them "back"?  I've been trying to take pictures of
> >>fry which are live-stained and need long (1-2 minute) exposures, but they
> >>move around much too much.
> >
> >At the risk of repeating what's easily found in the zebrafish book: Mesab
> >(a.k.a. tricaine, MS-222, or 3-aminobenzoic acid ethyl ester) works fine as
> >an anesthetic, and is readily reversible if you don't overdose the fish. A
> >final concentration of 0.05 mg/ml (in embryo water or tank water) should be
> >fine for larvae; if they're still twitching go up to 0.1 mg/ml. It's
> >important to adjust the pH of your solution to about 7, as Mesab is an
> >acid. It may also help to increase the viscosity of the medium, for
> >instance by mounting the fish in 2-3% methylcellulose.
> >
> >--Chi-Bin Chien
> Herwig Baier
> baier at
> University of California, San Diego
> Department of Biology
> La Jolla, CA 92093-0366
> Phone: (619) 534-2526
> Fax:   (619) 534-8866

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