Sex Ratio Forecast; Emergency nursery; Small tanks

["Maladorno, Dionigi \(DRUG;Nutley\)" <DIONIGI.MALADORNO@roche.com>]

swaldron@slip.net (Steven J. Waldron)
wrote: <<<<<Sex Ratio Forecast
(...)  Imagine this scenario:  At the end of the
dry season when water bodies have shrunken, fish are more exposed to
predation, flashy, territorial males have been heavily predated upon, it
may be more adaptive to produce more males to fill this vacancy when the
first rains of the wet arrive. (..)>>>>

I do not know much about these issues, but what you write
sounds quite interesting to me.






I want to share with the List a little emergency trick I just used
to try to give better chances of survival to a spawn of newly 
hatched A. cacatuoides.

The fry of my first cacatuoides spawn are adult now, most have
been sold or auctioned, but I kept the two best males and three
females in a 55 gal, with a school of eight quite peaceful silver
dollars
(the spotted type) and a medium size angelfish. My intention
was to just hold them for future exchanges with fish club
members.
One female spawned in the past, but the eggs where soon gone.
A few days ago I found another guarding a batch of eggs on the
side of one of the small flowerpots (she had dug a small pit in the 
sand under the flowerpot). She was aggressively defending them 
against the other females and the two males, while I could bet
I saw on the face of the silver dollars an expression that sounded 
like "keep growing them, we will stop by later....".
When after a couple of days I saw that she had moved the newly 
hatched wigglers inside the pot, I decided that she deserved some 
help. I have no available tank space elsewhere (the A. maciliensis 
fry grow amazingly slowly, and three tanks are still taken by them), 
and the temporary nursery I have was too narrow for the flowerpot.
So, I took a 1 gallon plastic water bottle (not the cylindrical type, 
but the type roughly cubical), cut out the top leaving the handle,
tied a nylon twine to it, filled it with aquarium water up to 2" from
the edge,
and suspended it in the aquarium holding it in place with the twine tied
to 
a leg of the stand.  The edges are about 2" above the water. I then run
a small airline in it, with moderate bubbling (no airstone).
Finally, while the female was observing what the hell I was doing from
inside the flowerpot, I gently blocked with my hands both sides of the 
flowerpot, lifted it with all its contents, and placed it in the
floating bottle.
Now, two days later, the fry are free swimming, while the female still
threatens any fish that comes too close, whose shade she can still 
see through the translucent plastic.   I change 2/3 of the water in the
nursery every day (about half with aquarium water, the other half with 
tapwater). If they make it, I will soon be able to put them in a tank
with
their one-month old uncles......



For reasons of space, I keep all my apistos in small tanks, 2.5, 5  and
10 gallons with lots of live or plastic plants. 
Until now, I never lost any males to female aggressivity after 
spawning, since I remove them or partition the tank within 24 hours
after
mating occurs. If hideouts are available, the male avoids major beating
by hiding, and there is plenty of time (say, a few days) for finding
another
residence for him. Even a partitioned 5 gallon is not too bad for the
first 
weeks (females and fry on one side, male on the other), provided that 
good water changes are made several times a week. 
Like others, I found the plastic needlework screens from rag shops very
effective and cheap tank dividers.


Dionigi