TRIGGERS
by Bart van Dijk
First published in the newsletter of the Vancouver Aquatic Hobbyist Club
Aquarticles
The guinea pigs we bought on impulse. They did not have a home yet and the cardboard
box had to be cleaned. I blocked the kitchen door and let the guys loose. All during the
cleaning I heard alternately subdued noises and very frantic nail scratches on the tiled
floor. I stood there utterly amazed. "What were these guys doing?" - they would
walk calmly out from under the fridge and then make a mad dash back underneath, over and
over again. It took me an hour of watching to realise that they were obeying their built-
in command: "Know your way home from anywhere so that you can make it from, in this
case, anywhere in the kitchen to under the fridge." Care to guess how long it took me
to catch the guinea pigs? Yes it might have taken two hours that one night, but once I
learnt to whistle the very high sound that guinea pig mothers use, I found I could freeze
them to the spot no matter what they were doing, and they never figured out that it was
not their mom for all the six years they were our pets.
A friend of mine in the Queen Charlottes worked as a faller, cutting down huge trees.
During lunchtimes he delighted in observing the animals around him. He managed to just
about tame a raven, who would come every lunchtime. He started wondering how this raven
could manage to fly through all those branches and never hit anything. As his cut
progressed away from the raven's area he began to notice how the raven did not fly to him
any more "as the crow flies" but was zigging and zagging, and once the idea hit
him it was obvious: the raven was flying the old flyways through the now non-existent
trees.
Spotty our terrier cross was a bright animal; show her a trick and almost straight away
she would do it - learning ability bar none. Yet for all of her eighteen years she would
bury the excess food in her dish by scooping the non-existent dirt from the kitchen floor
with her nose. Each night she would lay down all the standing grass in her bed by turning
around and around. Reading every other dog's territory with her nose was of utmost
importance on our evening walks, but it was useless information to her because she knew
full well that our lot was her lot, and she knew the boundaries to the nearest inch. She
knew that severe penalties always followed crossing the line, but any cat in full flight
would make her forget.
* * *
The countryside is bare and boy is it dry… The rain begins to fall, and the dried
up ponds and puddles are actually beginning to show a little bit of water….. The
little killifishes in their eggshells have been waiting for this ! Depending on the area
where they live, they have waited two months to ten months, and quite often when the
previous year's rains failed to come, they have been waiting between fourteen and twenty
two months.
But the first rain brings with it a huge dilemma for these guys. Is this the rain that
will continue and put enough water in the pools to make a full life cycle possible, or
will it dry up shortly and cause certain death if you have hatched? A tough decision to
make, especially when you are inside a half millimetre eggshell, stuck in the mud.
If a "small" rainfall occurs you will get wet alright but that is about all;
everything else stays the same:
1) The temperature of the water around you will be about the same as the mud you are in,
instead of dropping significantly.
2) You did not get tossed around by the little streams in the pool.
3) The infusoria have not "hatched" in the huge quantities that consume most of
the oxygen, before the copods, daphnia, start eating them.
4) You cannot feel any microworms moving through the mud.
5) The water depth does not cause any pressure on your egg shell yet.
… So there you go, measure all parameters until you are absolutely sure. However
there are always "buts"...
-If you wait until the water depth is too great you will not be able to make it to the
surface for that vital first breath to blow up your swim bladder (if you don't make it you
will always be a belly slider).
-If you wait a few days you might just be out in the cold when it comes to staking out a
territory - the guy who gets there first is usually more determined and manages to hang
on. And what is more, you might not be able to complete a full life cycle at all.
Everything might be dry again before your own eggs are safely back in the mud again.
* * *
O.K., so YOU buy a pack of eggs at our Auction. Know now that you have to convince
these little fish that the time is right…..
First you have to make sure the eggs have been dry for their normal dry period and then
the battle is on:
- You put the peat with the eggs in a flat dish, cover them with about two inches of, for
them, cold water of about 55 degrees. Good for you, you have now convinced the daredevils
(say about 20%) that this is the time, and you have made sure that they can get to the
surface for that gulp of air.
- But you would have convinced another 30% if you had shaken them around a bit, so gently
spend some time breaking up all the peat lumps.
- Unlike "regular" fish, killies don't have yolk sacs, and you have to feed them
immediately on hatching anyway, so a good dollop out of your infusoria culture will lower
that oxygen content, and will convince another 20% to hatch. Similarly a finger full of
microworms will improve your hatch rate once again.
- But it takes drying the peat once again after the first hatch, keeping it dry for about
a month or two and going through the same procedure again to finally convince the diehard
pessimists to come out also.
Good luck! To see all those guys hatch, usually the day after you put the water in,
makes it all worthwhile.
A huge thank you to all the Killie Club members who must have become very tired of
answering all my questions during the past two years. I promise to keep on learning more
and more by observing my own killies. I will keep on varying their environment until they
are as happy as they can be.
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