[Killietalk] Inspecting killifish eggs in peat

[Wright Huntley <whuntley at verizon_net>]

Since there are many variables involved in the development of eggs 
stored in damp peat, it behooves the good breeder to learn the difficult 
process of finding and examining them for development. It also can cut 
the legs from under the crook, when his feedback has your messages that 
"he sent me no eggs in the peat." You cannot say that without 
considerable confidence in your ability to find eggs.

In this note, I'll outline how I trained myself to find and inspect 
eggs. It wasn't that easy, and it took some serious effort to get good 
at it. The results are worth it.

Picking eggs from mops is a big help. The easily-seen eggs are good eye 
training for seeing them in poorer-visibility peat. Finding eggs in peat 
from prolific spawners, like GAR can also be a help. The eggs are big 
and clear, and if there are lots of them, they are visible all over the 
surface of the peat. Look at as many eggs as you can in as many 
situations as possible. It trains your eye and brain to detect more 
obscure spherical shapes where none should be.

I tried many ways, but my final, preferred technique, uses a shallow 
white bowl and a halogen reading lamp. A light table is best, so 
illumination shines through a thin layer of peat and eggs. If you 
position a 50W+ halogen lamp across the bowl from you, the light shining 
down is reflected from the white bowl through the eggs and thin peat, 
much like a light table. A regular incandescent bulb is worthless, and a 
fluorescent bulb even worse. You need a strong point-source of light to 
make the glint from spheres obvious. Sunlight is quite good, but any 
distributed light source makes finding eggs much more difficult. Use a 
halogen reading lamp, about 45 degrees from the bowl bottom so light is 
reflected right into your face.

Start by counting eggs in peat with known eggs. Drag a little peat 
across the bare bowl bottom at a time, watching for the spherical shape 
and (usually) amber color of peat-stained eggs. When you have counted 
all the eggs in a small sample, count again. Confidence rises as the 
counts begin to agree. Now you are ready to start the final training and 
test.

Boil and rinse a peat pellet, and dry to typical pipe-tobacco dampness. 
Now, add exactly one small egg and mix well. Start a 10 minute timer, 
and stop when you have found that egg or the timer goes off.

I repeated this training/test until I found the egg at least 9 times out 
of ten within the ten minutes. At that point, I had some confidence in 
my ability to find eggs in peat. At 75, my reading glasses are no longer 
strong enough, so I use a jeweler's loupe or a head-band magnifier to 
assist my vision. Use what you need to have your eyes and brain relaxed 
enough to get really good at spotting eggs. Some young folks, 
particularly those who are near-sighted, need no magnification. Others 
have more difficulty with pattern recognition and need more practice, 
better light or magnification.

Once eggs are found, judging development is pretty easy.

Clear eggs are undeveloped and have a ways to go.

Eggs with visible embryo are getting there, but may not be ready.

When the eye is developed and has a solid gold ring all the way around a 
black pupil. it is ready.

My rule of thumb is when at least 2/3 of the eggs are in this latter 
state, it is time to dunk them. Remove hatched babies from the peat in 
no more than 2 days, using an eyedropper and gently stirring through the 
peat from one end to the other to drive the hiding ones out to be sucked 
up. Redry the peat and try again in 3 weeks or so. This depends on 
species so know your species and if they have programmed variable hatch 
times. Some SA annuals may need months.

Good luck,

Practice!

Wright

-- 
Wright Huntley - 805 Valley West Cir., Bishop CA 93514 
whuntley at verizon_net 760 872-3995. Cell 760 937-2276

Join the AKA at http://www.aka.org/aka/modules/content/index.php?id=9.
Archives are at http://fins.actwin.com/killietalk/
Modify your subscription at http://www.actwin.com/mailman/listinfo.cgi/killietalk