Aquaponics Digest - Tue 10/19/99
Message 1: Aggressive Male Tilapia
from "Tan Cheow Nam(mailandnews)"
Message 2: Re: Aggressive Male Tilapia
from Adriana Gutierrez & Dennis LaGatta
Message 3: Re: Aggressive Male Tilapia
from "Barry Thomas"
Message 4: Re: Aggressive Male Tilapia
from "Wendy Nagurny"
Message 5: Re: Aggressive Male Tilapia
from "James Rakocy"
Message 6: Re: Aggressive Male Tilapia
from "Peter D. Rau"
Message 7: Re: Aggressive Male Tilapia
from "Peter D. Rau"
Message 8: Fwd. - Salmon hatchery info from Nick Jones
from S & S Aqua Farm
Message 9: Inflation Fans, In or Out?
from Jones Nick A PSNS
Message 10: Re: Aggressive Male Tilapia
from Marc & Marcy
Message 11: Re: Inflation Fans, In or Out?
from Ronald Polka
Message 12: Re: Aggressive Male Tilapia
from "Barry Thomas"
Message 13: RE: Inflation Fans, In or Out?
from Jones Nick A PSNS
Message 14: Re: Aggressive Male Tilapia
from "Peter D. Rau"
Message 15: Re: Aggressive Male Tilapia
from Marc & Marcy
Message 16: Re: Aggressive Male Tilapia
from "Peter D. Rau"
Message 17: unsubscribe
from Roger Marius Ciceron
Message 18: Re: Aggressive Male Tilapia
from Bertmcl
Message 19: Re: Aggressive Male Tilapia
from
Message 20: Re: Aggressive Male Tilapia
from "JAY MYERS"
Message 21: Re: Aggressive Male Tilapia
from "JAY MYERS"
Message 22: Re: Aggressive Male Tilapia
from dreadlox@cwjamaica.com (michael kent barnett)
Message 23: Attachment may be a worm/virus from Jay
from "Nick Jones"
Message 24: Re: Attachment may be a worm/virus from Jay
from "Nick Jones"
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Subject: Aggressive Male Tilapia
From: "Tan Cheow Nam(mailandnews)"
Date: Tue, 19 Oct 1999 16:48:41 +0800
I have been trying to introduce more tilapia to my existing tank with a male
one. However, this male tilapia has been very aggressive towards whichever
new fish in the tank. It practically attacked them until they are dead or
the new ones get so bruised and fungus infection set in and they eventually
died.
Is there anyway to overcome this? Or do I have to get rid of this particular
one? Any advice would be appreciated.
Thanks & Regards
CN
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Subject: Re: Aggressive Male Tilapia
From: Adriana Gutierrez & Dennis LaGatta
Date: Tue, 19 Oct 1999 05:05:23 -0400
This may sound brutal but I know that one fish breeder recommends
cutting the lips on male tilapia so that they cannot harm other fish.
> I have been trying to introduce more tilapia to my existing tank with a male
> one. However, this male tilapia has been very aggressive towards whichever
> new fish in the tank.
> Is there anyway to overcome this? Or do I have to get rid of this particular
> one? Any advice would be appreciated.
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Subject: Re: Aggressive Male Tilapia
From: "Barry Thomas"
Date: Tue, 19 Oct 1999 12:10:18 +0100
> This may sound brutal but I know that one fish breeder recommends
> cutting the lips on male tilapia so that they cannot harm other fish.
You're quite right Adriana, it does sound brutal. Also, unnecessary,
time consuming and pointless. I cannot see how mutilating an animal to
stop it from damaging others improves the sitiuation. We are not talking
about pruning a tomato plant here but something with a fairly well
developed nervous system. I can't say for certain whether solutions like
this cause the fish distress but would rather not take the chance.
I have the greatest respect for your views and and am grateful for the
help and info you give on this list but I really do not think that this
kind of thing (or the acceptance of the "body count" method of system
evaluation mentioned by others) is what we should be aiming for. The
fish (or whatever animal) does, of course, get eaten in the end anyway
but I feel that we do have some kind of responsibility to ensure
reasonable conditions/practises in the meantime.
Surely it is better to discover _why_ this happens and alter conditions
to avoid it? In this particular situation, removal of the single rogue
fish or altering conditions in the tank seems preferable?
Barry
barrythomas@crosswinds.net
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Subject: Re: Aggressive Male Tilapia
From: "Wendy Nagurny"
Date: Tue, 19 Oct 1999 08:42:40 -0400
Give the the new female the spawning tank. Place the male in his own tank.
After the female had settled in and is gravid, add the male to the female's
tank. Your male is too territorial to place any intruders in *his* tank,
so make the male the newcomer.
Wendy
>I have been trying to introduce more tilapia to my existing tank with a
male
>one. However, this male tilapia has been very aggressive towards whichever
>new fish in the tank. It practically attacked them until they are dead or
>the new ones get so bruised and fungus infection set in and they eventually
>died.
>
>Is there anyway to overcome this? Or do I have to get rid of this
particular
>one? Any advice would be appreciated.
>
>Thanks & Regards
>CN
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Subject: Re: Aggressive Male Tilapia
From: "James Rakocy"
Date: Tue, 19 Oct 1999 08:46:17 -0400
Cutting off the upper mandible is a standard technique. The male kills by
scraping two sets of sharp teeth against each other. When one set is
missing, it cannot get a bite. Isn't this a better approach than having a
lot of fish chewed to death? This is not a rogue fish. In a small
confinement every male will behave this way. In a larger area they will
just establish territories and fight at the borders. If you use a very high
density, then territoriality will break down and they will not even spawn.
If you want to establish a spawning family in a small aquarium with one male
and several females and the male is larger than the females, place a wire
mesh in the tank, selecting a size that only the females can pass through.
They then have a refuge. Tilapia are not good aquarium fish. Jim R.
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Subject: Re: Aggressive Male Tilapia
From: "Peter D. Rau"
Date: Tue, 19 Oct 1999 09:46:04 -0500
Hello all,
I'm new to this list and tilapia aquaculture, but not new to keeping all
kinds of fish.
I have found that providing a section of PVC pipe large with large enough
diameter for the female to enter, but small enough to keep the male at bay
works with most members of the cichlid family. PVC is inert and durable.
This is an alternative to the mesh with the hole small enough for the
females to get through.
I'm currently researching my options in Tilapia farming and have found that
there are a lot of filtration and broodstock options out there. I've also
found that most of the systems can benefit from slight addition or tweaking
to make them much more efficient. I would be interested in hearing about
your setups and experiences. Feel free to email me directly at
prau@tcs.tulane.edu if your comments are something that has already been
discussed on this list.
Peter D. Rau
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Subject: Re: Aggressive Male Tilapia
From: "Peter D. Rau"
Date: Tue, 19 Oct 1999 09:47:54 -0500
How is your tank setup? Is it bare? or is there shelter for the fish?
"Tan Cheow Nam(mailandnews)" wrote:
> I have been trying to introduce more tilapia to my existing tank with a male
> one. However, this male tilapia has been very aggressive towards whichever
> new fish in the tank. It practically attacked them until they are dead or
> the new ones get so bruised and fungus infection set in and they eventually
> died.
>
> Is there anyway to overcome this? Or do I have to get rid of this particular
> one? Any advice would be appreciated.
>
> Thanks & Regards
> CN
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Subject: Fwd. - Salmon hatchery info from Nick Jones
From: S & S Aqua Farm
Date: Tue, 19 Oct 1999 09:47:21 -0500
Nick Jones kindly tracked down and forwarded the info on the salmon hatchery
he'd heard about. Thanks for pursuing this, Nick. I've looked at the
pages, and it certainly looks interesting (especially the part about grant
funding - wouldn't we all like to have some of that!). Glad to see some
positive moves to control the water quality of aquaculture systems effluent.
Paula
---------------------------------
Paula,
Have been getting a classical bureaucratic run around this
week trying to find this info but here are the links and one page. There are
two articles, with quite a bit of information, non-tech for the most part
though. I did not know if the graphic was appropriate for the forum.
It seems one hurdle was convincing the Fish and Wildlife
people that I was not some activist, wanting to complain, file a complaint,
or protest. (They get beat up a lot by the press)
The F&W water quality person that I spoke to on the phone
said that they were going to settle the solids out before taking the water
to the greenhouse. One factor in this decision is the large amount of
sediment washed down from upstream.
I don't know if they are planning on only one greenhouse,
but with 6-7 Kgal/day it might be interesting.
This is supposedly going to be in the city of Issaquah, Wa.
nick
http://splash.metrokc.gov//wlr/Greenhse.htm
http://splash.metrokc.gov/dnradmin/press/990927gh.htm
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Subject: Inflation Fans, In or Out?
From: Jones Nick A PSNS
Date: Tue, 19 Oct 1999 07:54:20 -0700
Question for owners/installers of double film, inflated void greenhouses.
Written information found recommends installing inflation fans where they
draw outside air.
We live in the Pacific Northwest where humidity seldom drops below 85
percent, and generally is in the 95-100 percent range, why would I want to
draw cold air from outside, to fill the void which is supposed to be
insulating the greenhouse from outside cold air?
tnx....nick
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Subject: Re: Aggressive Male Tilapia
From: Marc & Marcy
Date: Tue, 19 Oct 1999 09:51:41 -0600
Are there special techniques, tools and training materials
available for this upper mandible removal process? I wonder
if the experimental approach could cause excessive trauma
and/or the loss of a valuable fish?
Marc Nameth
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Subject: Re: Inflation Fans, In or Out?
From: Ronald Polka
Date: Tue, 19 Oct 1999 10:12:29 -0600
At 07:54 AM 10/19/1999 -0700, you wrote:
>Question for owners/installers of double film, inflated void greenhouses.
>Written information found recommends installing inflation fans where they
>draw outside air.
>
>We live in the Pacific Northwest where humidity seldom drops below 85
>percent, and generally is in the 95-100 percent range, why would I want to
>draw cold air from outside, to fill the void which is supposed to be
>insulating the greenhouse from outside cold air?
>
>tnx....nick
>
Nick
This is a rule of thumb. Under most environmental conditions the outside
air will have a lower dewpoint than the interior greenhouse air. It is
desirable to use inflation fan inlet air with the lowest possible dewpoint
to minimize condensation within the envelope during cold weather. Given the
choice between inside and outside fan inlet air you should choose the
source that has the lowest dewpoint. Heating cold outside air is really not
an issue here. If you were to go through the numbers of calculating the
mass flowrate of the air moved by your inlet fan, multiplied by the
specific heat and required temperature rise within the envelope to reach
thermal equilibrium you will find that the energy required to heat this by
conduction through the inner layer of plastic is literally next to nothing
compared with other greenhouse heat losses. If examined in detail you will
find that if you blow warm air into your envelope that has been heated
within the greenhouse you will actually increase the greenhouse roof losses
because you will raise the exterior skin temperature slightly and the skin
temperature is directly related to conductive, convective, and radiant
losses to the atmosphere. You are moving air that is insulated by the
double layer of plastic to an area that is insulated by a single layer of
plastic. This then causes the temperature gradient across your envelope to
become flatter resulting in higher losses if allowed to equilibrate under
these conditions.
Your unique weather conditions of very high relative humidity may require
experimentation to determine if an inside or outside air inlet is better,
dependant upon what happens with moisture inside the envelope. Whatever you
decide heating the envelope air is irrelevant in the overall greenhouse
heat balance.
Ron Polka
Southwest Technology Development Institute
New Mexico State University
Box 30001, Dept 3SOL
Las Cruces, NM 88003
rpolka@nmsu.edu
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Subject: Re: Aggressive Male Tilapia
From: "Barry Thomas"
Date: Tue, 19 Oct 1999 17:55:16 +0100
> Cutting off the upper mandible is a standard technique.
Yes, my previous post was aimed at the principle rather than Adriana
herself, apologies if it seemed otherwise.
However, burning people at the stake, slavery, carpet bombing of cities
and vivisection for cosmetics etc have all been standard techniques and
though - from certain points of view - they worked fairly well, have
all been abandoned as the disadvantages and true costs to _all_
concerned have been recognised and alternative's found. Ok - fairly
extreme examples but you see what I mean?
> The male kills by
> scraping two sets of sharp teeth against each other. When one set is
> missing, it cannot get a bite. Isn't this a better approach than
having a
> lot of fish chewed to death?
Isn't this a bit like asking whether you'd rather be eaten by a lion or
a tiger? Both questions lack the - rather desirable - option of avoiding
either fate.
> This is not a rogue fish. In a small
> confinement every male will behave this way. In a larger area they
will
> just establish territories and fight at the borders. If you use a
very high
> density, then territoriality will break down and they will not even
spawn.
That's my point - adapting your system to accomodate (and preferably
cooperate with) the behaviour of the plants and creatures it contains is
surely better all round than enforcing conditions which promote
conflicts and then simply hacking bits off when things get too
difficult?
Barry
barrythomas@crosswinds.net
PS I didn't know about the territorial behaviour of tilapia - I'm trying
to learn as quickly as possible but there are only so many hours in the
day :)
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Subject: RE: Inflation Fans, In or Out?
From: Jones Nick A PSNS
Date: Tue, 19 Oct 1999 10:13:45 -0700
Hi Ron,
I guess the long/short is that if I knew the numbers and
what to do with them once I had them, I would go with that.
So, if we find that we have a considerable amount of
condensation in the envelope, then duct some other source to the fan inlet.
Heat gain/loss from inside or outside is not an issue,
condensation is.
tnx....nick
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Subject: Re: Aggressive Male Tilapia
From: "Peter D. Rau"
Date: Tue, 19 Oct 1999 12:34:58 -0500
Barry,
Most of the fish that belong to the "Cichlidae" family that live in Africa
are extremely territorial. Particularly the larger mouthbrooders, such as
tilapia. No matter how many hiding places you supply, the dominant bruisers
are going to kick some butt. Females are only slightly less aggressive in
most species of "Cichlidae."
The marvelous thing about African fish is that they have an attitude of "the
more the merrier." They go from being extremely aggressive and territorial
in small groups to almost lethargic in dense groups. They can't find a
target to focus on in dense groups, so aggressive behavior subsides.
Another option that sometimes works is to provide a "dither" fish. A
"dither" fish is a tough, but non-aggressive target fish. With a "dither"
fish in the tank, most "Cichlidae" become loyal partners and stop killing
each other in order to defend its territory from the "dither" fish.
I don't know if "dither" fish are being used in aquaculture setups, but I
have used them in the aquarium industry for over 20 years with great
success.
Peter D. Rau
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Subject: Re: Aggressive Male Tilapia
From: Marc & Marcy
Date: Tue, 19 Oct 1999 11:28:42 -0600
> Another option that sometimes works is to provide a "dither" fish. A
> "dither" fish is a tough, but non-aggressive target fish.
This fish survives then? It is not injured? Do the tilapia
attack or merely defend territory?
> With a "dither"
> fish in the tank, most "Cichlidae" become loyal partners and stop killing
> each other in order to defend its territory from the "dither" fish.
Is the fish not a tilapia? Could you give examples of an
appropriate dither fish for tilapia or a reference source to
study?
Do the fish need to have physical structures of some type to
identify as "home" or territory?
Very interesting idea.
Marc S. Nameth
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Subject: Re: Aggressive Male Tilapia
From: "Peter D. Rau"
Date: Tue, 19 Oct 1999 13:00:28 -0500
Marc,
I have not experimented with dither fish with tilapia yet. I am theoretically
relating
what I have used in the past with fish similar to tilapia in an aquarium
setting. The "dither"
fish is generally a different peaceful but tough type of fish that provides a
distraction for the
fish, in my case the fish I was breeding. The library should have some
aquarium books that
contain information on the use of a "dither" fish. Particularly any books on
"cichlids." There
is a book called "Tank Busters" that may have some information as well. It
will take some
experimenting to find a fish that attracts the attention of tilapia, is fast
enough to avoid their
attacks, and doesn't bother their spawning attempts if that is the scenario.
Tilapia live amongst piles of rocks with lots of open water in the wild. Any
structure is going
to make the tilapia more territorial, but will provide refuge for the pursued
fish. As I said, PVC
sections make good cover. Large INERT rocks are good as well. Be careful
with rock work.
It is heavy and can leach undesirable metals/minerals/etc. into the water.
Most public aquariums
create structures from concrete (acid washed and cured before using) or
fiberglass.
Hope this helps some. What size tanks are your tilapia in? How many fish per
tank?
Peter D. Rau
Marc & Marcy wrote:
> > Another option that sometimes works is to provide a "dither" fish. A
> > "dither" fish is a tough, but non-aggressive target fish.
> This fish survives then? It is not injured? Do the tilapia
> attack or merely defend territory?
>
> > With a "dither"
> > fish in the tank, most "Cichlidae" become loyal partners and stop killing
> > each other in order to defend its territory from the "dither" fish.
> Is the fish not a tilapia? Could you give examples of an
> appropriate dither fish for tilapia or a reference source to
> study?
>
> Do the fish need to have physical structures of some type to
> identify as "home" or territory?
>
> Very interesting idea.
>
> Marc S. Nameth
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Subject: Re: Aggressive Male Tilapia
From: Bertmcl
Date: Tue, 19 Oct 1999 16:32:19 EDT
CN,
Try clipping upper lip - it will re-heal very shortly. Yes we had male to
kill females.
Bert
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Subject: Re: Aggressive Male Tilapia
From:
Date: Wed, 20 Oct 1999 10:30:10 +0930 (CST)
Here is australia we have trouble with our murray cod being too
aggressive. To over come this we stock them in high density and that
seems to stop them from eating each other. I don't know whether it will
work with tilapia breeding though.
Andrew
On Tue, 19 Oct 1999 Bertmcl wrote:
> CN,
>
> Try clipping upper lip - it will re-heal very shortly. Yes we had male to
> kill females.
>
> Bert
>
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Subject: Re: Aggressive Male Tilapia
From: "JAY MYERS"
Date: Tue, 19 Oct 1999 22:29:46 -0500
begin 644 Happy99.
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Subject: Re: Aggressive Male Tilapia
From: "JAY MYERS"
Date: Tue, 19 Oct 1999 21:43:31 -0600
Have you clipped the males upper lip ?
Jay
----------
> From: Tan Cheow Nam(mailandnews)
> To: aquaponics@townsqr.com
> Subject: Aggressive Male Tilapia
> Date: Tuesday, October 19, 1999 2:48 AM
>
> I have been trying to introduce more tilapia to my existing tank with a
male
> one. However, this male tilapia has been very aggressive towards
whichever
> new fish in the tank. It practically attacked them until they are dead or
> the new ones get so bruised and fungus infection set in and they
eventually
> died.
>
> Is there anyway to overcome this? Or do I have to get rid of this
particular
> one? Any advice would be appreciated.
>
> Thanks & Regards
> CN
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Subject: Re: Aggressive Male Tilapia
From: dreadlox@cwjamaica.com (michael kent barnett)
Date: Tue, 19 Oct 1999 00:09:24 +0100
Aquaponikers, recently there was a reply regarding stocking of a pond as
a function of the growbed size, (and vice versa). Some papers from James
R. were mentioned.
James, (and others) do you offer these papers on a given server? I have
read a lot of your other works in the form of extension docs. Is there a
site where most of your work can be downloaded?
Right now in particular, this "phasing in" and "phasing out" of stock
density to growbed size and plant maturity is of great importance to
me..
Anyone with some online docs or pointers?
I am also interested in folks who have done exactly what was spoken
about.. the phasing in of fingerlings, to feeding rate and how do I
match this to growbeds size and plant maturity, Any given knowns for
grabs, (would save me a lot of time) :> would be grateful for online
coaching..
Or at least some pointers...
Thanks... MIke,
Soon fishygrandaddy..
James Rakocy wrote:
>
> Cutting off the upper mandible is a standard technique. The male kills by
>
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Subject: Attachment may be a worm/virus from Jay
From: "Nick Jones"
Date: Tue, 19 Oct 1999 21:17:15 -0700
The last email received from Jay M contained an attachment which is =
recognised by Symantic as a worm. A type of virus. It should be deleted =
and not executed.
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Subject: Re: Attachment may be a worm/virus from Jay
From: "Nick Jones"
Date: Tue, 19 Oct 1999 21:19:15 -0700
http://www.symantec.com/avcenter/venc/data/happy99.worm.html
This web address will explain.
nick
-----Original Message-----
From: Nick Jones
To: aquaponics@townsqr.com
Date: Tuesday, October 19, 1999 9:12 PM
Subject: Attachment may be a worm/virus from Jay
=20
=20
The last email received from Jay M contained an attachment which is =
recognised by Symantic as a worm. A type of virus. It should be deleted =
and not executed.
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