[Killietalk] re: Killifish Temperatures

["Allan Semeit" <azkillie at quixnet_net>]

Allan from Arizona writes -

Tyrone Genade stated that South Africans have failed to keep some
Aphyosemions - "such lovelies such as A. louesense, occelatum, raddai,
cameronense, punctatum, cyanostictum and even rectogoense alive during the
hot summer with tanks at 27 to 28°C (if we are lucky). We even struggle with
australe some summers so to say that "cool" killies do not propser at high
temps is a myth is to ignore a wealth of evidence from other warm climates."

My response - That is probably true for all of us.  With our higher summer
temperatures, I have not had much success with those particular species.  I
agree that SOME Aphyosemions require temperatures below 75 degrees
Fahrenheit and will not survive at higher temperatures.  The point I am
trying to make is that there are MANY others that not only survive, but seem
to appreciate the high 70s and even low 80s.  In my experiences, A. australe
did best at about 80 degrees.  Others that seem to like the higher temps
would include most Chromaphyosemions as well as other lowland species
(i.e. - striatum, gabunese, etc.).

Tyrone further stated - "The heat can be beaten with proper feeding but
oxygen is a limiting factor that cannot be escaped. You have told us a lot
about how your killies survive 80°F but not how they do so? How well are the
tanks planted? Plants supply oxygen. Eggs left on the plants survive better
than those picked for many reasons one of which is oxygen.

My response - When I moved to Arizona, almost 7 years ago, I left all of my
glass tanks behind.  Most of my tanks were the 2 1/2 gallon plastic Critter
Keepers.  These tanks contained mops and either an air stem or filter
(sponge or box).  Eggs were incubated in small plastic Glad brand
containers, and the fry have been raised in plastic shoe (primarily) and
sweater boxes.  As I have moved up from an apartment to buying a house, I
have been able to gradually add glass tanks.  These are almost all 10-gallon
tanks.  Except for a few tanks with Java Moss or Java Sword, they have
usually been "bare" tanks with only mops and filters.  My experiences are
based upon these conditions.

In Arizona, there is almost no temperature fluctuation in our house during
the summer months. It does not cool down appreciately at night.  My house is
kept between 78-82.  We turn the thermostat down to 78 in the evenings when
we get home.  Turn it up to 80 when we go to bed, and leave it between 80-82
when we leave for work.  I have a spare bedroom for the fish and there is no
separate heating or cooling for it - the temperature is whatever the ambient
temperature of the house is.

This summer I did begin experimenting with planted aquaria. At this time, it
is impossible to speculate as to whether or not the plants have been
beneficial.  They do provide additional oxygen during the day (or at least
when the tanks are lit), but also consume oxygen when the lights are off.
Their greatest benefit, in my eyes, has been in removing nitrate and other
compounds.  Also, my objective in going to a more "natural" set-up was to
raise the fry with the parents - and skip the extra work of picking eggs,
incubating the eggs, and rearing the fry separately.  For some killies, this
works.

In summary, my set-up have been fairly "bare-bones".  To offset possible
oxygen deletion and other factors due to the limited amount of water, I try
to limit my 2 1/2 gallon breeder tanks to a pair or no more than 4 fish
(usually two pairs).  At the other extreme, the 10-gallon tanks can be
packed with anywhere from 10-30 adult and sub-adult fish, again with only a
sponge filter and mops.  And, they seem to breed best when the temperatures
get above 78 degrees.

The bottomline - while some killies (speaking primarily of Aphyosemions) do
best when kept in the low 70s, others are more adaptable and may actually
prefer warmer temperatures.  Knowing this may help a hobbyist discover the
killies that are easiest for him or her to keep and raise.



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