Dropsy is not a disease, it's a
name for a fishes shape. It means generally swollen and scales standing out
from the body. .I have never seen a case of true dropsy cured in the 40 years
I've been with fish and have only seen one fish spontaneously
Most fish with this problem survive for only 2-3 weeks but
sometimes as many months. Often the belly becomes reddened shortly before
death. 99% of case I've seen have mainly a mixed bacterial infection (aeromonas
hydrophila and mycobacteriosis). Aeromonas enters the body through intestines
in the winter or spring and through ulcers, heron or parasites wounds.
Once inside the fish the bacteria infect the kidneys and the liver.
Failure of either one of these organs can course dropsy symptoms. Dropsy
especially from liver or kidney damage can be so severe as to finally cause
primary organ failure itself.
You should immediately use fish
anaesthesia. You must NEVER allow fish to die in a pond once dropsy has shown
itself. Don't start with injections as none will work, the internal organ are
beyond help and you are risking a secondary infection to start that you may not
be able to stop.
You should be treating the fish in hospital tanks - it
is surprising how many Koi keepers do not have them. Start look for how it came
about in the first place.
This is a classic case of dropsy. Note the swollen eyes and
gill covers and the reddening of the belly and fin pits. I destroyed this fish
within 5 mins of seeing the animal. This is an advanced case and you should
never allow a fish to get in this condition and DIE in the pond. As you can see
from the pictures, sepsis is well advanced, and if fish can feel pain this one
would have been in agony - I would suspect the fish had been ill for some days