How clean is too clean for a fry tank?

On Sat, 18 Nov 2006 18:23:44 +0100, Marco Schwarz
wrote:

Hi..

[...described emergency room fry tanks...]

Well.., I'm sure and certain that fish fry generally love to
eat living micro food and that it will enjoy to grow up in
micro life rich tanks..

Personally I come from a fish keeping tradition where
vacuuming and weekly filter cleaning is completely unknown
but weekly water changes of 50%+ are very common..

I was doing weekly changes because my life has been really hectic. It
was also good because there were so many little critters for the young
fry to feast on. I would have thrown that away being too clean.

Now I'm doing about 80% changes every couple days and feeding much
more. That's about when the tanks start to take on a bit of an odor.
Growth rate has been great. I'm inclined to believe ppl who claim
that frequent large water changes aid in growth rates. It does seem
to slow somewhat when I stretch out the water changes.

And this is why I'm used to vote for big enough and stable
(cycled) tanks with a lot of mulm or mud - and of course a
lot of helpful plants like elodea, hornwort and java moss
for feeding growing fish fry..

I'm with you.

I'm experimenting with breeding now.

What kind of fish..?

At the moment Opaline Gourami and Black Lace / Golden Angel hybrids (I
don't know if there is a name for that). Nothing terribly difficult
as I'm a newb.

Well try to imagine the green algae on the substrates to be
"woods" where a lot of useful bacteria and bacteria eaters
are used to live (== bio film)..

Yes which is one of the reasons I think it's a good idea. From what I
understand there is some belief that exposure to water quality
problems and certain bacteria in early stages of development can lead
to deformities. So I wonder if commercial breeders see algae as a
2-edged sword? and that's why they are unwilling to pay to support it
with artificial lighting. But such claims are so unspecific I wonder
if it is superstition.

Before these spawns I read a lot about the prevalence of deformities,
and therefore the need to cull, and how it is common for growth rates
to be so dissimilar that is possible for faster growing fry to eat the
smaller ones. I have culled the slowest growers, and lost a lot due
to my own carelessness (and lack of desire to raise many hundreds of
fish) but interestingly those things I read have not panned out at
all. I'm inclined to believe the algae and critters were helpful in
early development.

Hi..

At the moment Opaline Gourami and Black Lace / Golden
Angel hybrids (I don't know if there is a name for that).

Fine..

[...hobbyist breeding versus commercial breeding...]

Well.., hobbyist breeding and commercial breeding sometimes
seem to be two different universes. ;-)

Before these spawns I read a lot about the prevalence of
deformities, and therefore the need to cull, and how it is
common for growth rates to be so dissimilar that is
possible for faster growing fry to eat the
smaller ones.

Hmm., in nature smallness means danger of life and only the
smartest and fittest fry will survive. The magic word is
selection. That's real life and the necessity of selection
is the first lesson a hobbyist breeder has to learn. Well
sounds a little bit precocious I know..

I'm inclined to believe the algae and critters were
helpful in early development.

Good luck..!
--
cu
Marco