Koi keepers often have stories
to tell of how their koi disappeared for some unknown reason. First to
be blamed is normally the resident cat, or the next door family dog.
Fact is that your ordinary house cat will be so well-fed that he will
hardly bother a mouse, let alone a koi.
In South Africa the main reason
for koi disappearing is aerial attacks from predatory birds. Kingfishers
and cormorant must surely be rated as the most effective fish predators.
Since they feed almost exclusively on fish, they will, if given the
opportunity, return every day for their meal until there is none left in
your pond. The bright coloured ones will be taken first. The red and
white Kokaku's and yellow Ogons and the tri-coloured Sanke. Perhaps a
brown or black koi will remain too elusive for these birds.
Other birds like the hammerkop,
grey heron and hadeda are less likely to take fish since they prefer
other small prey like frogs, platanna, lizards and insects, but should a
fish come into view they will most certainly try to catch it. The most
disconcerting thing is that these birds do not know their own limits and
will actually try to catch fish to large for them to handle and will
leave wounds that could cause their death or leave them on dry land to
dry. In suburban areas these birds can quickly switch to an all fish
diet if that is the only food they can easily prey on.
Ponds that are in rather quiet
parts of the garden are better targets for aerial attacks, while ponds
that are shallow will leave your collection easy prey. Cover the pond
with bird net of some sort. The larger your koi the larger the mesh size
can be and the less unsightly it will look. Some keepers prefer to
provide natural hiding places for their fish. Plants like water lilies,
a ledge or a pipe can be used. These obstacles in the water are not
recommended. It can hurt you fish, tend to make they skittish and hide
all day. Besides, quite a few fish need to be caught before the others
get the message.
In the rural areas keepers must
also be content to do battle with the clawless otter, water mongoose and
terrapins. Platanna will eat fish with a great appetite while sometimes
even your pet duck may not turn to eating small fish. And then we should
not forget about man, the ultimate predator who sometimes can do the
most inexplicable things to a koi collection.
Written for Animal Talk magazine --
© Servaas de Kock & Ronnie Watt