Fat Zebra Danio, Egg bound or illness?

[avgeek21]

I've had 2 healthy Zebras for over 2 years in a heavily planted 6
gallon tank (with 2 cardinal tetras and 2 rasboras.) One was always
chubby and the other slim, so I assumed I had a male and a female,
although I have never seen any evidence of spawning (except for the
first week I had them, when they were the only 2 in there I saw a
couple of zebra fry in the tank). So here it is 2 years later and
"male" now has a huge belly bigger than the "emales. He/she is acting
normal and does not have the "pine cone" scales, which I've read
indicate dropsy. Eggbound female or sick (or fat) male? Can't be a
female, can it? Could it have taken 2 years for it to become
reproductively mature and start producing eggs? So it must be a male
and he's either got some disease or is just a fat load. Perhaps a
parasite? I've read that 2 years is pretty long life for zebras, so
maybe he is not sick and is just getting a big spare tire in his old
age? Thanks.

[Tynk]

On Mar 3, 10:06�pm, "avgeek21" > wrote:
> I've had 2 healthy Zebras for over 2 years in a heavily planted 6
> gallon tank (with 2 cardinal tetras and 2 rasboras.) One was always
> chubby and the other slim, so I assumed I had a male and a female,
> although I have never seen any evidence of spawning (except for the
> first week I had them, when they were the only 2 in there I saw a
> couple of zebra fry in the tank). *So here it is 2 years later and
> "male" now has a huge belly bigger than the "emales. *He/she is acting
> normal and does not have the "pine cone" scales, which I've read
> indicate dropsy. *Eggbound female or sick (or fat) male? *Can't be a
> female, can it? *Could it have taken 2 years for it to become
> reproductively mature and start producing eggs? *So it must be a male
> and he's either got some disease or is just a fat load. Perhaps a
> parasite? *I've read that 2 years is pretty long life for zebras, so
> maybe he is not sick and is just getting a big spare tire in his old
> age? * *Thanks.

Hi there.
Just so you are aware, but not saying this is what your "male" has,
but Dropsy symptoms don't always include the pinecone look.
Dropsy isn't an actual disease in it's self, but a symptom.
It's swelling inside the body from excess fluid build up.
How's your water change schedule?
How much do you change and how often?
Were there any new fish added recently?

[avgeek21]

It's a 6 gallon tank and I change 2 gallons every 2 weeks. Even with
all the plants, with 6 fish my nitrate level does run in the 45-50
range and I've always worried about that, but the fish seem to do
fine. I have not changed or added anything recently so I think I can
rule out a parasite. I looked closely and noticed that one Harlequin
rasbora (over 1 year old) is also looking a little pudgy. Thanks for
the help.

[Tynk]

On Mar 4, 7:19�am, "avgeek21" > wrote:
> It's a 6 gallon tank and I change 2 gallons every 2 weeks. *Even with
> all the plants, with 6 fish my nitrate level does run in the 45-50
> range and I've always worried about that, but the fish seem to do
> fine. *I have not changed or added anything recently so I think I can
> rule out a parasite. *I looked closely and noticed that one Harlequin
> rasbora (over 1 year old) is also looking a little pudgy. *Thanks for
> the help.

Your problem most likely is not enough water changes.
Start doing a 20% water change weekly.
You say your fish seem to be doing fine, yet they aren't.
They are showing Dropsy symptoms which the #1 cause is poor water
conditions.
Sorry if that sounds harsh, (not trying to be).
You may have heard of "New tank syndrome", well there's also "Old tank
syndrome" where the nitrates get too high and start killing off fish.

[avgeek21]

> Your problem most likely is not enough water changes.
> Start doing a 20% water change weekly.
> You say your fish seem to be doing fine, yet they aren't.
> They are showing Dropsy symptoms which the #1 cause is poor water
> conditions.
> Sorry if that sounds harsh, (not trying to be).
> You may have heard of "New tank syndrome", well there's also "Old tank
> syndrome" where the nitrates get too high and start killing off fish.

I'll do that, thanks. The zebra died last night and the one rasbora's
belly is slowly getting bigger. Is there anyhting I can do in the
short term for this fish? In addition to more frequent water
changes, would using an antibiotic, lke Maracyn-Two, do anything for
this ailment? I still have 4 other "healthy" fish in the tank.
Should I isolate the bulging rasbora?

[swarvegorilla]

Cull and cull hard.
I am adding some cut and pastes from the zebra fish NG.
Nice and scientific for ya
;-)
Read and they will explain exactly what your dealing with.
Sorry so big but yea saved ya lookin for it!



*******

Hi Beth,
I have just a few things to add to the discussion on mycobacteria.
There seems to be a lot of hype and often over reaction to the
diagnosis mycobacteriosis in the zebrafish community. Atypical or
nontuberculosis Mycobacterium spp. are ubiquitous in aquatic
environments, persisting largely in biofilms. I would argue that if
you look hard enough, you will find it in all established zebrafish
systems. Many Mycobacterium spp. are resistant to common chlorine
disinfection. That's why it is also commonly found in municipal
drinking water distribution systems and swimming pools. A number of
these Mycobacterium spp. are documented pathogens of zebrafish,
however, they are opportunist pathogens causing chronic infections.
Asymptomatic carriers of mycobacteria are common in zebrafish with
the swimbladder and ovary being the most commonly infected organs.
There are strains of zebrafish that are more susceptible to
mycobacteria infections. In our experience, the TU strain is ten
times more likely to be infected compared to other wild-type strains.
There also appears to be some differences in virulence between the
different species and strains of Mycobacterium.

So with this background, what do you do? I am not a proponent of
nuking systems and starting over. You will most likely get the same
bug back. All Mycobacterium spp. respond poorly to antibiotics, so
this is also not a good option for fish facilities. Because of the
opportunist nature of bacterial infections in fish, your first focus
should be on husbandry and water quality. Stress lowers the immune
competency of fish. This includes any type of suboptimal water
quality (e.g. elevated nitrogenous compounds - including nitrate, pH
fluctuations) and other stressors (e.g. high stocking density, over
use). The other focus should be on lowering the exposure dose. All
pathogens have a dose response - the higher the exposure to
mycobacteria the greater the infection rate. To decrease the dose of
bacteria make sure that your UV is properly sized and maintained,
that cleaning procedures are adequate, and do not keep moribund
(sick) or old fish. Eliminating Mycobacterium from zebrafish systems
is not a realistic goal, it needs to be managed.

Let me know if you have questions. We are also always happy to give
feedback on your husbandry and water quality parameters. very best, -Jen



Jennifer L. Matthews, DVM, PhD
Zebrafish International Resource Center
Pathology and Health Services
5274 University of Oregon
Eugene, OR 97403-5274 <(()><
(541) 346-6028 ext. 14 <(()><
Fax (541) 346-6151



On Jan 23, 2007, at 8:07 AM, wrote:

> I work in a facility that is trying to establish a small Medaka and
> Zebra fish colony.
> Recently we discovered Mycobacteria in our Medaka which are on the
> same
> rack as our Zebrafish. One of the male Zebrafish began swimming a bit
> oddly and his abdomen became red as if bleeding internally or inflamed
> organs. He is has since been set to the pathologist for screening, but
> is assumed to have Mycobacteria as well.
> The facility Veterinarian and I have both done literature searches but
> find not treatment. Has anyone successfully treated or eliminated
> Mycobacteria from their fish and or system?
> Help is greatly appreciated from an inexperienced fish researcher.
> Beth Padnos
>
> _______________________________________________
> Zbrafish mailing list
>
> http://www.bio.net/biomail/listinfo/zbrafish



Hi,
You can also try to use some Kanamycin sulfate. You can purchase it at
aquaticeco. Before treatment shut down your UV bulbs and remove the
carbon from your filtration system. However it might not be very
realistic to treat the whole system for a couple of fish since you will
destroy all the bacteria ( nitrosoma and Nitrobacter) from your
filtration and endanger the all population of fish..

Olivier Paugois
Whitehead Institute
9 Cambridge Center
Cambridge,MA 02142
Tel: 617-258-5200



On Jan 23, 12:07 pm, "christian lawrence"
> wrote:
> The veterinarians that monitor this list may have different opinions on
> how
> to proceed (and correct me if I have made technical misstatements), but I
> would make the following GENERAL statements, based on experience:
>
> 1. If Mycobacteriosis is in your system, it is difficult, if not
> impossible
> to eliminate without "nuking" the system: sacrificing all of the fish,
> breaking down and sterilizing the system and components and starting over
> with SPF (or at least Myco free) fish.
>
> 2. If a facility has has Myco in the past, and it hasn't been "nuked", it
> still has Myco, even if things have since "cleared up" (no mass
> mortalities).
>
> 3. I think it not a crazy to guess that many populations of fish from
> long-term facilities carry one or more strains of Mycobacteriosis - even
> though personnel may be completely and blissfully unaware of it (I would
> love to see a wide-scale pathology study done on random samples from many
> places). The better the "conditions" (environment, diet, and genetics)the
> more chronic, low level the presentation of these strains Myco will be
> (will
> knock out only old or otherwise immunocompromised fish). The worse the
> conditions are, the more acute the outbreak. If your fish experience a
> big
> negative environmental effect, the low level, chronic Myco can easily
> become
> an all-out severe outbreak.
>
> 4. If you get fish from another lab, anywhere, that isn't certified SPF
> (ZIRC is for certain diseases, including Myco, I think, but who else?) you
> may very well be bringing in Myco, since as far as I know, bleaching eggs
> (particularly the brief exposure typical of most protocols) is not 100%
> effective at getting rid of it.
>
> 5. There may be problems if a different strain of Myco gets into a new
> environment - from what I understand, the levels of virulence can depend
> on
> the environment and populations infected.
>
> What does all of this mean, relative to your situation? If you're having
> a
> high level mortality event, and like most people, cannot afford to "nuke"
> the system and start over, I would do my very best to ensure that ALL
> environmental parameters are favorable and stable, cull aggressively, cut
> back on feeding, slowly lower the temp a few degrees and maybe up the
> salinity a bit and hope for the best. If you're not experiencing high
> level mortality, and routine pathology revealed that one of your normal,
> baseline level morts was infected with Myco, it certainly isn't cause for
> a
> dance party, but I wouldn't worry too much about it. I would just strive
> to
> ensure that husbandry protocols are optimal and stable and move on
> (carefully).
>
> The fact that you say that you're trying to establish a colony suggests
> that
> environmental parameters may not yet be stable. If this is the case,
> stabilization at favorable levels is absolutely key to solving the acute
> mortality problems that you may be experiencing.
>
> Good luck,
> Chris
>
> Christian Lawrence
> Brigham and Women's Hospital
> Karp Family Research Laboratories 06-004B
> One Blackfan Circle
> Boston, Massachusetts 02115
> Tel: 617.355.9041
> Fax: 617.355.9064
>
> -----Original Message-----
> From:
>
> ] On Behalf Of
>
> Sent: Tuesday, January 23, 2007 11:08 AM
> To:
> Subject: [Zbrafish] Mycobacteria
>
> I work in a facility that is trying to establish a small Medaka and Zebra
> fish colony.
> Recently we discovered Mycobacteria in our Medaka which are on the same
> rack
> as our Zebrafish. One of the male Zebrafish began swimming a bit oddly
> and
> his abdomen became red as if bleeding internally or inflamed organs. He is
> has since been set to the pathologist for screening, but is assumed to
> have
> Mycobacteria as well.
> The facility Veterinarian and I have both done literature searches but
> find
> not treatment. Has anyone successfully treated or eliminated Mycobacteria
> from their fish and or system?
> Help is greatly appreciated from an inexperienced fish researcher.
> Beth Padnos
>
> _______________________________________________
> Zbrafish mailing list
> /biomail/listinfo/zbrafish
>
> THE INFORMATION TRANSMITTED IN THIS ELECTRONIC COMMUNICATION IS INTENDED
> ONLY FOR THE PERSON OR ENTITY TO WHOM IT IS ADDRESSED AND MAY CONTAIN
> CONFIDENTIAL AND/OR PRIVILEGED MATERIAL. ANY REVIEW, RETRANSMISSION,
> DISSEMINATION OR OTHER USE OF OR TAKING OF ANY ACTION IN RELIANCE UPON,
> THIS INFORMATION BY PERSONS OR ENTITIES OTHER THAN THE INTENDED RECIPIENT
> IS PROHIBITED. IF YOU RECEIVED THIS INFORMATION IN ERROR, PLEASE CONTACT
> THE SENDER AND THE PRIVACY OFFICER, AND PROPERLY DISPOSE OF THIS
> INFORMATION.


The veterinarians that monitor this list may have different opinions on how
to proceed (and correct me if I have made technical misstatements), but I
would make the following GENERAL statements, based on experience:

1. If Mycobacteriosis is in your system, it is difficult, if not impossible
to eliminate without "nuking" the system: sacrificing all of the fish,
breaking down and sterilizing the system and components and starting over
with SPF (or at least Myco free) fish.

2. If a facility has has Myco in the past, and it hasn't been "nuked", it
still has Myco, even if things have since "cleared up" (no mass
mortalities).

3. I think it not a crazy to guess that many populations of fish from
long-term facilities carry one or more strains of Mycobacteriosis - even
though personnel may be completely and blissfully unaware of it (I would
love to see a wide-scale pathology study done on random samples from many
places). The better the "conditions" (environment, diet, and genetics)the
more chronic, low level the presentation of these strains Myco will be (will
knock out only old or otherwise immunocompromised fish). The worse the
conditions are, the more acute the outbreak. If your fish experience a big
negative environmental effect, the low level, chronic Myco can easily become
an all-out severe outbreak.

4. If you get fish from another lab, anywhere, that isn't certified SPF
(ZIRC is for certain diseases, including Myco, I think, but who else?) you
may very well be bringing in Myco, since as far as I know, bleaching eggs
(particularly the brief exposure typical of most protocols) is not 100%
effective at getting rid of it.

5. There may be problems if a different strain of Myco gets into a new
environment - from what I understand, the levels of virulence can depend on
the environment and populations infected.


What does all of this mean, relative to your situation? If you're having a
high level mortality event, and like most people, cannot afford to "nuke"
the system and start over, I would do my very best to ensure that ALL
environmental parameters are favorable and stable, cull aggressively, cut
back on feeding, slowly lower the temp a few degrees and maybe up the
salinity a bit and hope for the best. If you're not experiencing high
level mortality, and routine pathology revealed that one of your normal,
baseline level morts was infected with Myco, it certainly isn't cause for a
dance party, but I wouldn't worry too much about it. I would just strive to
ensure that husbandry protocols are optimal and stable and move on
(carefully).

The fact that you say that you're trying to establish a colony suggests that
environmental parameters may not yet be stable. If this is the case,
stabilization at favorable levels is absolutely key to solving the acute
mortality problems that you may be experiencing.

Good luck,
Chris



Christian Lawrence
Brigham and Women's Hospital
Karp Family Research Laboratories 06-004B
One Blackfan Circle
Boston, Massachusetts 02115
Tel: 617.355.9041
Fax: 617.355.9064

-----Original Message-----
From:
] On Behalf Of

Sent: Tuesday, January 23, 2007 11:08 AM
To:
Subject: [Zbrafish] Mycobacteria

I work in a facility that is trying to establish a small Medaka and Zebra
fish colony.
Recently we discovered Mycobacteria in our Medaka which are on the same rack
as our Zebrafish. One of the male Zebrafish began swimming a bit oddly and
his abdomen became red as if bleeding internally or inflamed organs. He is
has since been set to the pathologist for screening, but is assumed to have
Mycobacteria as well.
The facility Veterinarian and I have both done literature searches but find
not treatment. Has anyone successfully treated or eliminated Mycobacteria
from their fish and or system?
Help is greatly appreciated from an inexperienced fish researcher.
Beth Padnos

_______________________________________________
Zbrafish mailing list

http://www.bio.net/biomail/listinfo/zbrafish