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8/4/2008
Case study:
In early June (2nd) new fish were added to a
small pond, they were obtained from the original dealer.
Up to that point all fish in the pond had been healthy for
the past three years. The pond owner observed the new fish
were injected with the antibiotic chloremphenical, which was
presumably the 3rd dose. They were told that since the fish
had been in quarantine for 3 weeks and had given each 3
shots, they did not need to quarantine them, so they were
not. Two days later one of the new fish had bulging eyes
and by the next day its thoracic area had swollen and it
died. They returned it to the dealer who indicated it had
an internal infection. At this point the other new fish
appeared completely healthy.
Later that
month (June 22), they obtained another new fish from the
same dealer. They were told it had been through the normal
quarantine and prophylaxis treatment.
Two days
later, they noticed a small (confined to 4 scales)
underlying red spot (lesion) on one of their original fish
with some white superficial material. At this time they also
noticed the newest fish wasn't eating effectively (it would
come up to food, but infrequently got close enough to mouth
it). The disregarded it initially.
The following day
they put the ill fish with lesions into a 10 gal. hospital
tank with 2 Tbsp salt and started it on a daily 250mg
Ampicillin regime. The next day they noticed an
underlying swelling (resulting in a slight pine-coning) and
a small white area at the center of the abscess, so they
started it on Fungus Clear (nitrofurazone, furazolidone, and
potassium dichromate), dosed at one tablet/ 4 days. They
also started medicated fish food (sodium sulfathiazole 2.3%)
3x/day.
On June
28, 6 days after purchase, the fish that had been having
trouble eating was noticed to have swelling of its mouth.
So it was also placed in the same hospital tank, and
presumably diagnosed as mouth rot.
I was
contacted on July 2nd, by that time a third fish
had developed mouth rot and fin rot on his tail and also
placed in the hospital tank.
At that
point they had kept up the above treatments, and also they
had been giving 500 mg tetracycline and Maroxy (stabilized
chlorine oxides) because the maladies were not resolving and
the original fish had secondarily developed 3, pinhead-sized
white dots on its tail that should not have developed under
an antifungal regime. The treatments at this point were
not working. The fish with the abscess its underlying
swelling has gone back to about normal but the redness has
widened. The other fish’s mouth had become necrotic, losing
the anterior edge of the lower lip and apparently resulting
in a compound break of the mandible.
When I arrived, I
noticed the water was clear, the pond had adequate
filtration and circulation, and the water chemistry was
normal. We anesthetized and skin scraping on several of the
fish. I found a few costia, and flukes. Of note is that
normally under the microscope you will see many different
kinds of various bacteria, there weren’t any in this
situation which leads me to believe the environment was
relatively sterile from all the product which had been used,
but yet none of those had been completely successful at
resolving what parasites the fish actually had. Below is the
treatment plan we devised based on those results.
1) Anti-fluke
treatment - July 5-July 12
2) Salt Treatment -
July 5 - continuing for 2 weeks to raise pond [salt] to 0.3%
for 2 weeks to kill Costia and other susceptible parasites.
3) Tricide-Neo (T-N)
Treatment - All fish to receive daily treatments for all
fish except the unaffected one, which will only get two
treatments before returning to the pond.
4)Feeding
Ad-lib (~3x/day)
antibacterial food from PetSmart, and then transitioned to
Medi-Koi on July 10 when PondRx shipment received. Pellets
suppl. with 1-2 diced orange slices / day.
5) Water Quality
Daily monitoring of
water while fish are ill
Later it came to
light that the dealer informed the pond owner that the fish
were infected with the bacteria Aeromonas (presumably done
by culture and sensitivity testing) Baytril injections were
then started on the remaining fish.
Despite treatment,
all but one fish died.
Lessons to be
learned from this:
1) Quarantine,
quarantine, quarantine
It’s never ok to
bring fish home without quarantining them. In this case
another significant concern is that the fish were injected
presumably with chlorenphnicol. This antibiotic can lead to
deadly anemia, or destruction of red blood cells, in a very
few people or animals. The risk is small but it is real and
this drug is infrequently used any longer in veterinary
medicine because of it.
2) These fish were
given two kinds of antibiotics, ampicillin and tetracycline.
Antibiotics in the water are not well absorbed. Although
these medications are available over the counter now, there
will come a time very near in the future when they will not
be. Prescribing antibiotics should only be done by a
veterinarian. An antibiotic injection without the guidance
of a veterinarian is practicing medicine without a license
and against the law.
3) These fish did
not have fungal infections. Treating them with antifungal
medications, I believe, lowered their immune system and
hoped make them more vulnerable to parasitism. One of the
medications in the antifungal treatment is nitrofurazone,
which has been known to be cancer causing and should only be
handled with gloves.
4) Only purchase
form a reputable fish dealer with a qualified aquatics
veterinarian overseeing their facility in order to properly
prescribe antibiotics, correctly identify parasitic disease
outbreaks, and have the advanced testing available to
culture for specific bacteria to ensure the proper
medications are prescribed. Ask about it before purchasing
any fish.
Had these fish been
quarantined first, then treated for costia and flukes, they
may not have developed secondary bacterial infections
requiring antibiotic injection. This is where the expertise
of a veterinarian may have saved money, heartache, and also
protected everyone involved from the potential dangers of
some of the products.
Bottom line:
Minimize your risk by only buying from dealers with a good
relationship with an aquatics veterinarian, and quarantine
your fish.
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