Re: [RML] M. preacox fry death

Gary Lange (gwlange at
Sat, 31 Jul 1999 15:49:51 -0500

27 is an idea temperature to keep rainbow fry. That really is a bit too
high to comfortably keep the adults for the long haul though. One of the
biggest problems for most people for fry is that they don't keep them warm
enough in the beginning. You could even have them higher than 27, you just
have to feed them more. BTW I think that I really get better hatches and
more fry surviving when I move the eggs to a clean tank. A new tank doesn't
have much fungus to get to the eggs. Once they start hatching then I add a
well established sponge to the bare tank. I you go about medicating the
tank make sure you do a lot of water changes before you start spawning your
fish if you plan to leave the fry in that tank. I don't think the
medication does the fry any good. If you're picking up velvet from your
killifish it might be worthwhile to have a separate net for that tank or
place the nets in really hot water before using in the rainbow tank. For
treating velvet I've had good luck with Mardel's Copper Safe.

>The temp of the tank is 27 deg C. The same temp I bred them at.
>The killies are generally kept cooler.

... If it was ammonia (which I
doubt) the parents didn't seem to be effected.

It's a real easy test to check for ammonia. Fry are much more sensitive
than adults. If you are "guessing" at velvet you might as well check some
of the more likely parameters first.

G. incisus really spawn like any other "general" Melanotaenia, Chilatherina
or Glossolepis. Give them a big enough tank for their size, plenty of water
changes and a good diet and they can't help but breed. They certainly are
not comfortable at low pH's though. That lake is alkaline and Jerry even
makes reference to the fact that the fish do not like acid pH. He states pH
range of 7.2 to 7.8. If you can still find a copy of Rainbowfishes, in
nature and in the aquarium it would be worth the trouble. One concern I
have found with the NG red is that the males can get a bit aggressive with
the females, especially in too small of a tank. If that is the case you may
have to separate them until you are spawning them, then separate them again.
A 4 inch male can be a bit of a bully. I seem to get much better egg
production using smaller fish.

>Has anyone got any advice on spawning G. incus?
Also, do their colours fade with decreasing pH? I did a water
change last Friday. For the whole evening he was an unbelievable
luminous red. This has now faded again. He is +/- 10cm long. Other
males I've seen his size were a constant scarlet red; how ever I
noticed that they were kept in hard alkaline water. My fish is
presently in a mixed community tank with soft water and a low pH.

Gary Lange
gwlange at
Rainbowfish Study Group of North America