Re: NANFA-- Rivulus marmoratus

R. W. Wolff (
Sat, 1 May 2004 23:41:29 -0500

I had good luck having a female spawn for me. I kept her in a small tank,
with dark brown gravel, and a mop. I found eggs in the mop on occassion, but
usually got the most eggs out of the gravel. This was a very occassional
thing. I would get a handful of eggs, and then nothing for months, maybe one
or two here and there. I had two males come of these spawnings. One died for
some reason, maybe it jumped out, I don't remember. The other male went to
someone in KY, but I never found out what happened with the college persons
school project with these fish.

After I passed them along, with a number of females, I lost the rest of the
fish. I kept them in my tap water which was close to rain water, far from
hard or brackish.

The things I tried to get the males, but not sure if any of them did the
trick. I used a clear container to incubate the eggs. I kept them cool. I
used tannic stained water to incubate the eggs. My guess is the soft acidic
water, high light amounts, and coolness might have replicated a time of
plenty, versus hot , salty and dark. If lots of rain and sun were going on,
the water would become less brackish, probably be cooler, and the eggs laid
all over, some ending up in brighter locations. When its hard times, low
water would be more brackish, hot, and the eggs probably hidden in leaf
litter, in crab burrows, or under logs. I read the hemaphrodite is probably
an adaptation to the harsh environment.

Ray W.
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