A Help Call
When I received a call from a friend that he was losing his
fish, I was concerned. But when he said twenty-one of his koi
had already died, two last night, and a couple more were
“isolating and not eating” I decided to make a house-call.
Upon arriving, I looked at the pond. The fish, for the most
part looked active and healthy. There were one or two fish that
were not swimming around and seemed to be exactly as he said. He
also had two fish, recently deceased, in the freezer awaiting
necropsy. The water was not clear, with large quantity of
suspended particulate matter and evidence of uneaten food (which
also could have been recently discharged “eaten” food that
returned to the pond in almost the original state) on the liner
fold near the bottom.
The pond has four waterfalls and several skimmers, several
bottom drains and a heavy filtration system. I checked the
filters. All were immaculate. This koi pond is shared with
numerous pet water turtles. The homeowner was asked to do water
tests. He came out of the garage with a multitude of test kits,
all of which were antiquated and came up with neutral or
negative results. He now realizes the tests are expired and will
replace them.
He sent his wife to the
neighborhood market for Oil of Cloves so we can do
a scraping and gill snip on one of the live, isolating fish. The
fish also showed considerable engorged capillaries in pectoral
and ventral fins, had a torn ventral fin, but otherwise looked
okay. Upon checking the gill tissue, it showed marked
deterioration, with gray-brown areas throughout the gills. Is it
significant that the fish was not gasping at the surface?
According to the homeowner, all the fish that died had simply
seemed to rest in the bog areas, not swimming, but not gasping
either. They seemed to lose interest in life. Many were gravid
females, but not all.
In the two necropsied today, both were females and the ova
were brown and small. One fish was 10” and the other 24” and
“ripe”. Both also had extensive gill deterioration; however I
don’t know how long they may have been dead before the homeowner
got them into the freezer. By the time I saw them they had
sunken eyes. Is this something that happens to fish when they
die? Very curiously, both, especially the smaller fish, had
almost white liver. Initially I thought I was moving aside some
fatty tissue, but soon realized this was the liver, or the fish
did not have a liver (of which I was doubtful!) Or is this
really white fat tissue?? I checked everything under the
microscope and found nothing but one dead fluke, or what looked
to be a dead fluke. I could locate no living parasites. The gill
tissue was badly blanched and parts were simply eaten away.
The live fish we did the scraping on was placed in a
quarantine tank with fresh water that does not share water with
the main pond. The homeowners were instructed to add aeration to
both ponds. They also will cut feeding in half. They will do a
50% water change today, another one tomorrow, followed by a
third one the next day. [He is using Sodium Thiosulfate to
dechlorinate new water.]
My friend needs to look at the food he is feeding and was
recommended to switch to Legacy Koi & Goldfish Foods for better
nutritional sustenance, and to increase the fishes’ stress
resistance. He knows to look for the undigested-looking feces as
a sign he is either not feeding correctly or feeding the wrong
food.
He also knows now that the reddened fins indicate a stressed
fish.
He will remove the shubunkins to reduce the bio-load in the
main pond, since he now understands the stress of overcrowding
and its ultimate destruction.
After losing twenty-one koi, he still has too many
inhabitants in the pond. Ah, but now he realizes it and is ready
to do something to save the rest! He’s going to take my advice
and contact the Koi Lab if he loses another fish, to get
directions on sending the fish for necropsy, to the people who
REALLY know what they are doing… Meanwhile, he says he’s going
to proceed with heat treatments and assume the worst (KHV).
by Carolyn Weise, Ecological Laboratories, Inc.
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