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Posted by Rob Stradling on July 21, 2006, 8:08 pm
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I have a pair of Synodontis catfish in a community tank. I don't know the
precise species because the supplier didn't either, and lots of research
has only told me which Synos they're *not* :-)
My question is this: is it normal and healthy for there to be a dramatic
difference in their growth? I've had them for about a year or a little
more, and they were both identically sized at around 3-4cm when I bought
them. Now one of them is a good 11-12cm long, and fat; the other has not
grown at all that I can percieve. If anything, it has shrunk! They both
seem healthy, and squabble playfully for space in a bogwood hideout, but
one is now fully five times the mass of the other. Although the large
fish can obviously be a bully at times, the little one doesn't seem to
struggle to get food, or suffer anything worse than damaged pride in
their tussles.
No information I can find suggests that there's a marked difference
between growth rates of the sexes, but from what I can tell the larger
fish's development is quite normal, with the other one being unusual. But
they're almost certainly from the same egg batch, and have lived in the
same tank! Can anyone explain / theorise on what might be going on, and
whether I should be concerned?
Thanks in advance for any wisdom recieved.
--
I'm a cosmopolitan sophisticate of culture and intelligence,
The culmination of technology and civilized experience.
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Posted by Fishman on July 22, 2006, 3:42 am
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>
> I have a pair of Synodontis catfish in a community tank. I don't know the
> precise species because the supplier didn't either, and lots of research
> has only told me which Synos they're *not* :-)
>
> My question is this: is it normal and healthy for there to be a dramatic
> difference in their growth? I've had them for about a year or a little
> more, and they were both identically sized at around 3-4cm when I bought
> them. Now one of them is a good 11-12cm long, and fat; the other has not
> grown at all that I can percieve. If anything, it has shrunk! They both
> seem healthy, and squabble playfully for space in a bogwood hideout, but
> one is now fully five times the mass of the other. Although the large
> fish can obviously be a bully at times, the little one doesn't seem to
> struggle to get food, or suffer anything worse than damaged pride in
> their tussles.
>
> No information I can find suggests that there's a marked difference
> between growth rates of the sexes, but from what I can tell the larger
> fish's development is quite normal, with the other one being unusual. But
> they're almost certainly from the same egg batch, and have lived in the
> same tank! Can anyone explain / theorise on what might be going on, and
> whether I should be concerned?
>
> Thanks in advance for any wisdom recieved.
>
>
>
>
> --
> I'm a cosmopolitan sophisticate of culture and intelligence,
> The culmination of technology and civilized experience.
I'll offer two suggestions:
Your 2 syno's arn't the same species - several species are very similiar.
Alternatively the smaller one may have a congenital abnormality which has
retarded it's growth.
Certainly different sexes of the same species have different maximum sizes
and growth rates.
Usually with Syno's the females are up to say 25% larger but that doesn't
fit your circumstances.
NOTE
Hardly any Syno's are bred in captivity, most are wild caught.
(The exceptions: some of the Lake Tanganika species and the true upside down
Syno)
So your statement, "they're almost certainly from the same egg batch" - is
unlikely.
HTH.
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Posted by Rob Stradling on July 22, 2006, 12:41 pm
Please log in for more thread options Fishman ><(((°> wrote:
> I'll offer two suggestions:
> Your 2 syno's arn't the same species - several species are very similiar.
> Alternatively the smaller one may have a congenital abnormality which has
> retarded it's growth.
>
> Certainly different sexes of the same species have different maximum sizes
> and growth rates.
> Usually with Syno's the females are up to say 25% larger but that doesn't
> fit your circumstances.
>
> NOTE
> Hardly any Syno's are bred in captivity, most are wild caught.
> (The exceptions: some of the Lake Tanganika species and the true upside down
> Syno)
> So your statement, "they're almost certainly from the same egg batch" - is
> unlikely.
>
Thanks for your comments.
The pair were originally taken from a tank containing 20-30
similarly-sized specimens; hence my assumption that they were probably a
brood. Part of my original attraction to them was that they shoaled,
which is not behaviour one sees every day from cats.
As I ask around I think an otherwise-benign physical defect must be to
blame. Little Syno has lived this long, so maybe it's happy being a
tiddler?!
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Posted by Andrew Gratton on July 22, 2006, 3:50 am
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Well the first thing that comes to mind is that they are possibly two
different Syno's which would not suprise me, Most probably someone made a
mistake at the LFS where you got them, and considering they were bought
when they were tiny identification could be hard, as with most species of
Pleco's some have names some have numbers lol but when they all look so
alike it is almost impossible to tell them apart except in the wild,
As for the size difference it could be they are different species, or the
smaller one is not getting sufficient food although it looks like it might
be , If they are different species then the size difference could be huge
and you might end up with only 1 syno left, have you tried Planetcatfish
.com ? they hold a large database with photographs of most species.
HTH
>
> I have a pair of Synodontis catfish in a community tank. I don't know the
> precise species because the supplier didn't either, and lots of research
> has only told me which Synos they're *not* :-)
>
> My question is this: is it normal and healthy for there to be a dramatic
> difference in their growth? I've had them for about a year or a little
> more, and they were both identically sized at around 3-4cm when I bought
> them. Now one of them is a good 11-12cm long, and fat; the other has not
> grown at all that I can percieve. If anything, it has shrunk! They both
> seem healthy, and squabble playfully for space in a bogwood hideout, but
> one is now fully five times the mass of the other. Although the large
> fish can obviously be a bully at times, the little one doesn't seem to
> struggle to get food, or suffer anything worse than damaged pride in
> their tussles.
>
> No information I can find suggests that there's a marked difference
> between growth rates of the sexes, but from what I can tell the larger
> fish's development is quite normal, with the other one being unusual. But
> they're almost certainly from the same egg batch, and have lived in the
> same tank! Can anyone explain / theorise on what might be going on, and
> whether I should be concerned?
>
> Thanks in advance for any wisdom recieved.
>
>
>
>
> --
> I'm a cosmopolitan sophisticate of culture and intelligence,
> The culmination of technology and civilized experience.
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Posted by Rob Stradling on July 22, 2006, 1:05 pm
Please log in for more thread options Andrew Gratton wrote:
> Well the first thing that comes to mind is that they are possibly two
> different Syno's which would not suprise me, Most probably someone made a
> mistake at the LFS where you got them, and considering they were bought
> when they were tiny identification could be hard, as with most species of
> Pleco's some have names some have numbers lol but when they all look so
> alike it is almost impossible to tell them apart except in the wild,
> As for the size difference it could be they are different species, or the
> smaller one is not getting sufficient food although it looks like it might
> be , If they are different species then the size difference could be huge
> and you might end up with only 1 syno left, have you tried Planetcatfish
> .com ? they hold a large database with photographs of most species.
> HTH
Thanks for that.
Yes, I have looked there, and dozens of other places. Plenty of the
images look like mine but I can never see anything absolutely
definitive. I admire anyone who can! :-)
The nearest approximations I can find are:
A (large): http://www.planetcatfish.com/catelog/image.php?image_id=4256
B (small): http://www.planetcatfish.com/catelog/image.php?image_id=7051
The colourations here are a good match. When the pair were new (and the
same size) they were identical - sand/gold coloured, as in picture B,
but with more clearly-defined, rounded spots rather than those "camo"
patches. The large one has become much darker as it's grown with the
spots much less visible, so that it resembles picture A. The tiddler is
still the same, leopard-like scheme.
As I've said elsewhere, I think it hugely unlikely (though admittedly
possible) that they're different species, coming as they did from the
same large shoal. But they certainly wouldn't strike you as the same
species now!
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> I have a pair of Synodontis catfish in a community tank. I don't know the
> precise species because the supplier didn't either, and lots of research
> has only told me which Synos they're *not* :-)
>
> My question is this: is it normal and healthy for there to be a dramatic
> difference in their growth? I've had them for about a year or a little
> more, and they were both identically sized at around 3-4cm when I bought
> them. Now one of them is a good 11-12cm long, and fat; the other has not
> grown at all that I can percieve. If anything, it has shrunk! They both
> seem healthy, and squabble playfully for space in a bogwood hideout, but
> one is now fully five times the mass of the other. Although the large
> fish can obviously be a bully at times, the little one doesn't seem to
> struggle to get food, or suffer anything worse than damaged pride in
> their tussles.
>
> No information I can find suggests that there's a marked difference
> between growth rates of the sexes, but from what I can tell the larger
> fish's development is quite normal, with the other one being unusual. But
> they're almost certainly from the same egg batch, and have lived in the
> same tank! Can anyone explain / theorise on what might be going on, and
> whether I should be concerned?
>
> Thanks in advance for any wisdom recieved.
>
>
>
>
> --
> I'm a cosmopolitan sophisticate of culture and intelligence,
> The culmination of technology and civilized experience.