Page 8 - TBAS-may-2018

-8- TBAS May 2018 ....................
Taraschewski, 1987).
Schmahl recommends trichlorophon as a dip at 10 ppm for 3.5 hrs., but it
would be advisable to reduce this to 1.5 hrs. at 30°C, 86°F. Dr. Reeves recom-
mends using trichlorophon at 0 .5 ppm daily for five days (Reeves , 1986).

Gyrodactylus, [Fig. 3]
The gyrodacylids are small worms, 0.3 to I mm in
length which attach to the skin, gills, and fins . Each species
is very host specific and may even be specific to a particular
site on the host (Roberts, 1989, p. 263). The haptor consists
of two large hooks surrounded by 16 smaller hooks
(Reichenbache-Kli nke & Elkin, 1965 p. 69). A sucker is
located on the anterior end. Gyrodactylus usually parasitizes
the skin and less frequently, the gills, (Untergasser, p. 100).
This monogenean commonly affects discus.

(A) Life Cycle
All the species of this family are vivaparous meaning
that they produce living young instead of laying eggs. A
mature gyrodactylid will contain an embryo which contains
another embryo which contains still another embryo so that
a mature worm carries three more generations within itself
(Untergasser, p. 100). This gives it the capacity for rapid
reproduction should favorab le conditions arise. Epizootics
of gyrodactylids are a sign of poor maintenance conditions
and an epizootic of protozoans will often occur at the same
time (Roberts, 1989, p. 263).

(B) Treatment
Gyrodactylids can be effectively treated with formaldehyde, potassium
permanganate or with trichlorophon (Untergasser, p. 128). They can also be
treated with anthelmintic compounds , particularly Praziquantel. Since dactylogyrus
will usually also be present, however, the treatments will still have to be repeated.
See section under Monogeneans regarding treatment.

Dactylogyrus, [Fig. 4]
Dactylogyrids range in size from 0.1 to 2 mm; the posterior end contains 2
or 4 central hooks and 12, 14, or 16 surrounding hooks depending upon the
species. The anterior is doubly forked with a sucker and four or more black eyespots,
which are photosensitive so that the larvae are attracted to dark objects such as
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