Page 50 - Koi Net - On-Line Koi Magazine - Issue 78
P. 50
Costia is pear shaped and never used for wet mounts). Costia is pear shaped and White spot is one of the swarmers. Each swarmer must find another fish to
moves around with a rather moves around with a rather erratic or jerky motion, most serious parasite infect within 12 hours, but in the Koi pond this tips the
erratic or jerky motion. infections and if not
propelled by two tiny hairs at the narrowest end. This treated will cause balance in favour of the White spot, as the swarmers
narrow part of Costia is the feeding mechanism and significant numbers of can easily find a Koi to infect!
this also is inserted into the skin cells to digest the Koi deaths.
It is important to treat once White spot has been
content. Koi infected with Costia may have a greyish
detected, but the treatment only eradicates the free
colouring and often the white areas of skin have a
living stage. Once a swarmer has burrowed under
blood shot appearance – also termed stress.
the skin of the Koi it is not affected by the pond
White spot (Ichthyophthirius multifilis) treatment.
White spot is one of the serious spring time parasite Koi affected by White spot have characteristic white
infections and in the pond can cause significant pimples scattered over the body surface, including
numbers of Koi deaths. The picture opposite shows a the eyes and gills, the fish is listless, often with fins
mature White spot to the right of the gill tissue and clamped. In the late spring, early summer male Koi
smaller immature ones in the centre and left side. It often develop spawning rash, which may have the
may be seen the White spot is located inside the skin appearance of White spot but the skin has a rough
surrounding the gill. Once mature each single White feel, which extends to the pectoral fins. Spawning
spot will rupture the Koi’s skin, escaping into the rash is never found on the eyes or gills and these Koi
surrounding pond water where it will attach to a are fit and lively.
surface for a free living stage where it reproduces to
form up to three thousand immatures, known as
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