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Growth of Nothos
- To: KillieTalk at AKA_Org
- Subject: Growth of Nothos
- From: Brian Watters <Brian.Watters at uregina_ca>
- Date: Thu, 30 Aug 2001 14:15:58 -0600
- In-Reply-To: <200108301734.f7UHYS216790 at actwin_com>
- References: <200108301734.f7UHYS216790 at actwin_com>
Tyrone Genade wrote:
> On 30 Aug 2001, at 11:27, Paul Jablinski wrote:
> Hi Paul
> As well as testing my current mailing issue I thought I
> would address this question:
> > Would anybody out there know how long Nothos should grow
> > after one month of life after hatching? I heard that they breed after
> > 5 weeks after hatching - is this true???
> > Bro. Paul
> N. foerchi can be ready for action in 6 weeks.
> N. orthonotus takes about 8 as does rachovii.
> Kafuensis can take 12 weeks before all the fish have
> matured and sexed out.
> A lot of the time depends on tanks size and feeding.
> Feed well, grow them out in a big tank with frequent
> water changes and they will rocket into growth.
> Most can be ready for action in 8 weeks. A large
> proportion can be ready at 6. 4/5 weeks is pushing it
> but not impossible.
I agree with what Tyrone has written about the growth rate of Nothos
and would emphasize that growth rate in captivity will vary enormously
depending on the conditions under which the fish are being raised. If
the fish are fed heavily with a good varied diet, and given
plenty of space and clean water, they will grow at a
tremendous rate. Higher temperatures (within reason) will also promote
more rapid growth.
To give some specific examples:
About 3 weeks ago I hatched out various batches of Nothos, including a
small batch of about half a dozen N. flammicomantis Kisaki TAN 95-5.
I gave them plenty of space and in just 3 weeks they have reached a
size of just over an inch in length, are fully sexed out and the males
are starting to drive the females. In contrast, I have a few other
batches of various Nothos hatched out at the same time but comprising
an estimated 200-300 fry each and these, in spite of being
subject to the same feeding regimen, are quite a bit smaller with only
the largest (males) starting to sex out. Even though I have them in
larger tanks, they are still vastly more crowded than the N.
flammicomantis and their slower growth rate is the result.
A few years ago, I raised a very small batch of N. furzeri, the males
of which were sexable within 12 days after hatching and were driving
the females at 21 days.
N. ocellatus, which reaches a length of 7-8 inches when adult, will
initially grow at the rate of about one inch per week if fed well and
given adequate space.
There is very little documented information about the growth rate of
Nothos in the wild but I do know for a fact that N. orthonotus can
achieve a size in excess of 2 inches within 5 weeks from
hatching so one can assume that they would have started to spawn
when about 3 weeks old. I have also, on numerous occasions found
juvenile Nothos at certain locations and then gone back to the same
locations 2 weeks later and found near adult sized fish.
However, don't be too concerned if your Nothos in captivity do not grow
at the same rate as those in the wild. Nothos tend to keep growing
until they die, albeit increasingly more slowly as they mature. So,
given that your aquarium specimens will generally live for much longer
than those in the wild, they can still reach pretty impressive sizes in
Brian R. Watters
Professor and Head
Department of Geology
University of Regina
Regina, Sask. S4S 0A2, Canada
Tel: (306) 585-4663
Fax: (306) 585-5433
E-mail: Brian.Watters at uregina_ca
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