Fish Health - Post Mortems

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Post MortemsPlease contact me before sending any fish for a post mortem so that I don't get them out of the blue.
Tissue samples are sent for necropsy tests if my findings are inconclusive or I suspect a bacterial infection. I will tell you now - most come back with aeromonas hydrophila which normally when history is checked from poor conditions. However, sometimes the finding are pseudomonas flourescens which causes open ulcers and sometimes popeye.

If the findings are ascites, fin erosions, infection of the fin muscle or pseudomonas putida (which is famous for turning fishes bellies red just before death) then we may have a problem that is beyond just poor pond condition.

These last two infections do not come over night. They need deep investigation but I'm happy to say they are not all that common.

Most deaths in a well run Koi pond are fish problem not a pond problem and limited to a single fish.

Fish TB is one problem which must be acted on straight away. Mycobacteriosis or fish tuberculosis. is spread fish to fish by cannibalism and in the right conditions can infect many fish, with the symptoms showing in other fish over long periods rather thanall together. It can in theory take many years to show itself in all infected fish.

A fish under going a post mortem will have gill snips, spleen, kidney and liver spore tests. Additionally body scrapes for parasite, flukes and protazoans, swim bladder checks and intestine fluid tests.

I do not come to any finding until the fish as gone through a full post mortem, no matter what is found initially.

post mortem of fishThis fish died of sepsis. As you can see by the size of the gall bladder, this denotes the liver was about to fail. Secondly, the egg mass was sour and infected. The heart which I have extracted is pale and over sized should be full of blood.

This is the symptom of a stroke, which is the prime course of death. Also the fish was suffering from fatty degeneration of the internal organs see ( fat fish under health) - when I opened the fish up the internal organs just rolled out, as picture shows.

The fish had been dead 5 mins - for once I had arrived at client's in time to perform a post-mortem, as the fish was in i's last breaths of life.

post mortem - abscessThis is one of the largest abscesses I have ever seen on a large chagoi. Before being opened, the lump was bigger than a goose egg and had come up in 3 days.

There was 250ml of pink puss within the abscess, and I advised the client to let me put the fish to sleep, as by the size of the lump and the speed it had arrived this was the only safe course of action.

One should never attempt to drain an abscess of this size, as treatment would be futile.

post mortem - abscessHis son kindly assisted by keeping the abscess open so I could take this picture for my records.

I could find no injury which would account for this. He had this fish for 10 years and had lavished much love and care on his koi collection.

In a lot of cases no reason for the abscess can be found.