Page 5 - TBAS-may-2018

TBAS May 2018 .................... -5-
else proceed through free swimming ciliated larvae which find a new host
(Reichenbach-Klinke and Elkan, p. 67).
Monogeneans are usually host specific and are most often introduced into
the aquarium with an infected fish. Infected parent fish transfer them to all including
the smallest of their fry (Untergasser, p. 100).
A recent German survey conducted by STUA (Staatliches Tierartzliches
Untersuchungsampt [State Veterinary 6 Examining Office]) in Stuttgart, revealed
that the skin of 14.3% of the symphysodon specimens submitted was parasitized
by dactylogyrus, and 7.1% by gyrodactylus. The gills of 14.3% of the symphysodon
submitted were massively parasitized by dactylogyrus and/or gyrodactylus. Scealare
specimens on the other hand were skin parasitized only by Ichthyophtirius multifiliis
(Hartmann, 1989).

Symptoms of Host Fish
These gill worms literally tear out small pieces of the gill as they feed.
Seriously affected fish are retarded in their growth rate. I noticed that infected
juvenile fish would respire at a very high rate, and that after feeding they would
go to the surface and gasp for air.

Treatment:
The live monogeneans can be readily killed by formaldehyde, malachite
green, potassium permanganate or other oxidants, however, the concentrations
required to kill the eggs of dactylogyrus would be lethal to the fish so that the
treatment must be repeated at least two more times , once every third or fourth
day thereafter (Kohler, June, 90). The fish should not be returned to the tank in
which they were treated until it, as well as connecting equipment and siphon hoses,
have been cleaned out with a strong solution of bleach to kill any remaining eggs
of dactylogyrus.

(A) Formalin
Always maintain strong aeration when using formalin , since it reacts with
oxygen, thereby reducing the dissolved oxygen concentration in the water. One
hour dips of 200 ppm formalin can be applied with good results on juvenile discus.
If the fish must be treated in the tank in which they were originally residing, then
a very large water change should be made before the addition of formalin, and
again after the dip time has expired. Alternately , a long term treatment of the
water with a lower concentration of formalin can be used. A very large water
change should be made and formalin added to maintain a 10 to 15 ppm concentration.
This should be repeated on the second and the third day as well. Tests conducted
at Alabama Polytechnic Institute in Auburn, Alabama, showed that 99% control of
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