[Coral-List] Optimal fixatives for coral tissues??

Szmant, Alina szmanta at uncw.edu
Tue Jan 13 14:03:11 EST 2004

Hi Shelley:

I used a fixative called Helly's [also known as Zenkers when made as below with the ZnCl2] for many years and it works well for corals:

1000 gm Zn Cl2
500 gm K dichromate
20 L distilled water

Above is stable indefinitely.  For use, add 5 ml of formaldehyde (37 to 40 %) to each 100 ml of Helly's

Decalcification is critical to getting good coral tissue preps.  The folowing is better than straight HCl solutions:

0.7 gm/L EDTA
0.008 gm/L KNa tartrate
0.14 gm/L Na tartrate
99.2 ml/L conc. HCl (12N)

Change acid at least twice per day and keep removing crud from decalcifying surfaces (endolithic sponges, etc).  Wash for ca. 12 with running tap water (overnight) to remove acid before dehydrating to embed, etc.

Techniques were learned from PaulYevich, US EPA and found in a short  technical manual that is not generally available and I am not sure if it was published:

Yevich, P and C. Barszcz.  1981.  Preparation of aquatic animals for histopathological examination.  US EPA, Environmental Monitoring and Support Laboratory, Cincinnati Ohio USA

Dr. Alina M. Szmant 
Coral Reef Research Group 
Professor of Biology 
Center for Marine Science 
University of North Carolina at Wilmington 
5600  Marvin K. Moss Lane 
Wilmington  NC  28409-5928 
tel  (910)962-2362  fax  (910)962-2410 
email  szmanta at uncw.edu 

-----Original Message-----
From: coral-list-bounces at coral.aoml.noaa.gov
[mailto:coral-list-bounces at coral.aoml.noaa.gov]On Behalf Of Shelley
Sent: Monday, January 12, 2004 7:06 PM
To: coral-list at coral.aoml.noaa.gov
Subject: [Coral-List] Optimal fixatives for coral tissues??

Dear Coral-Listers,
  I would very much like to hear from scientists who are dealing with 
different fixation techniques for histological work on hard corals.  I 
have been using standard 5% seawater-buffered formalin, per 
recommendation from my supervisor.  However, I have had numerous 
conflicting suggestions from histologists, lab technicians and other 
sources that the following fixatives give better results: 4% formalin, 
10% formalin, 70% ethanol, and 73% ethanol, glutaraldehyde, Helley's 
fixative, etc.  (However, most of these people were not necessarily 
working on corals.)   The publications I have read also do not seem to 
have a standard procedure, or the fixative may be dependent on the 
intended usage.
      My questions are:  Is there an optimal fixative specifically for 
hard corals that can be used for several different kinds of 
histological/histopathological/microscopic procedures?  What kind of 
results have you gotten when using different fixatives?  I would 
appreciate any information you can share.  Please reply directly to my 
email address.  Thanks!

Shelley L. Anthony <shelleya at gbrmpa.gov.au>

PhD Student, CRC Reef Research Center
School of Marine Biology & Aquaculture
James Cook University
Townsville, QLD 4811  AUSTRALIA

Townsville, QLD 4810  AUSTRALIA

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