Re: [RML] Set up

Gary Lange (gwlange at stlnet.com)
Thu, 12 Nov 1998 20:54:52 -0600

I agree with some of Adrian's comments. I have found fry in the sump of my
flow thru system. Whether it's from eggs (unlikely, see Hansen's comments) or
from hatched fry, any survivors should be suspect, especially if the species
are similiar. In similiar species/tribes you can end up confusing the females.
However my sump is a 55 gallon tank so I put rainbows in there and they eat
the fry (now). I have a good sponge on the return flow so no eggs go back into
the tanks. Sperm, cross fertilization, so far from the thousands of eggs that
have been hatched & raised I haven't seen anything that looked strangely out of
place when I raised the fry. I have no knowledge as to how long a sperm lasts
but I have "assumed" that it isn't a very long time in bows. This is my
"reasoning".

I've noted for a long time that bows (Mel. Chil & Gloss) males when young often
haven't figured out how to fertilise eggs very effectively. When they are at
the 1.25 to 2 inch size they go thru the attempts at spawning but are often
unsuccessful producing very few fertile eggs. Females of the same size seem to
produce fertile eggs when placed with larger, more mature males. The smaller
males placed with larger females however still produce a lot of infertile eggs.
Now it could be that the males are still ill-equipped for the job but I think
it might also be that they might be a bit over-anxious :-) and let go too far
from the female's egg. If this is the reason that the young males have trouble
then there's a good chance that sperm isn't going to survive the trip thru the
sump and back toward another unfertilized egg.

Suggested Experiment - set up a tank with two good sized rainbowfish that are
known to be fertile. Use a tank divider or egg crate to separate the two fish.
Put a mop 3-4 inches away from the divider on the female's side. A well fed
female will put eggs in the mop regardless of whether a male is around so she
should oblige. If you wait a few weeks you should be able to see if sperm can
travel thru water. If you don't think the male will "help" you can always add
a female and a mop to his side of the tank. If the sperm travels then the
other isolated mop should contain fertile eggs too.

Gary Lange
gwlange at STLNET.com
Rainbowfish Study Group of North America
http://home.stlnet.com/~gwlange/rainbowfish.index.html

----------
> From: Adrian Tappin <atappin at ecn.net.au>
> To: rainbowfish at pcug.org.au
> Subject: Re: [RML] Set up
> Date: Thursday, November 12, 1998 1:44 PM
>
> At 09:57 12/11/98 -0800,Dan Simon wrote:
> >I want to set up a bank of 10 & 20 gallon tanks for the purpose of
> >breeding various 'bows. To keep expenses down I would like to utilize
> >a central filter and drill overflows in each tank. However, I am
> >wondering if it is possible for different types to cross fertilize
> >with this sort of set up ? (i.e. If the eggs or sperm were to get
> >drawn into the overflow and into the central filter and then back into
> >a different tank. Is this 1) possible and 2) likely ?
> >
> >Your thoughts are appreciate.
>
> I use trickle filters on all my large tanks and it is not unusual for eggs
> to be transported from the tank through the overflow, pass the prefilter and
> down into the sump where they hatch and you can see the fry swimming around
> in the sump. I guess the next step is that they could be suck up through the
> pump back into the aquarium again?
>
> Personally, I hate recirculating systems that are hooked up together because
> if you get a problem in one tank, you end up with it in all of them.
>
> Adrian.
>
> Adrian R. Tappin
> "Home of the Rainbowfish"
> http://www.ecn.net.au/~atappin/home.htm