Part 7 Fish Diseases and Health Management
years, probably due to better husbandry on farms and kill large numbers of ish within days. here is and a build-up of natural immunity within ish said to be no efective cure for sporozoan diseases populations.
once ish are infected. Diseased ish should be removed, euthanized and safely disposed of.
Detection/identification: ulcers that appear Good husbandry, notably hygiene, seems to
on medium to large goldish (usually ish larger help in minimizing the spread of the disease. In
than 60 mm), most commonly in spring or the author’s experience, although Pleistophora
autumn, are likely to be caused by GUD. (Note hyphessobryconis made an appearance, it was easily
however that ulcers on ish are relatively common managed and its impact was negligible. However,
and can have many causes, therefore not every this is almost deinitely only because species other
ulcer on goldish is necessarily caused by GUD.)
than neon tetras were afected. he disease has
Treatment: the disease can be treated with the caused huge problems in major neon-producing
antibiotic doxycycline at 7.5 ppm as an indeinite areas until farms were cleaned up. bath, or in the diet at 1 to 2 grams of doxycycline
he most efective defence is to make absolutely
per kg of food, fed for at least 10 days.
sure that incoming broodstock are not infected, and remain so. If detected, every possible efort
Bacterial gill disease (BGD)
must be made to prevent its spread, and ultimately, to eliminate it.
Detection/identification: this is a common
disease in farmed goldish. Fish become lethargic Neon tetra disease
and stop feeding. Gill lamellae, which may be noticeably damaged, become pale and mucousy.
Pleistophora hyphessobryconis, (sometimes
Fish which are unable to obtain suicient oxygen also spelled Plistophora) which is responsible for
may rise to the surface or position themselves in the well known ‘neon tetra disease’, is perhaps
the best known sporozoan disease in tropical
Treatment: a dirty environment and ish, most notably in neon tetras, though other
overcrowding of ish in culture conditions are tetra species and other families have also been considered to be major contributing factors in found to be susceptible. Although sporozoa in outbreaks of the disease, so avoiding these is the general are recognized as having the potential irst step in controlling the disease. BGD can be to be very destructive, Pleistophora is relatively treated with antibiotics but because several types slow-developing and may take months to cause of bacteria can cause it, it may be necessary to test mortalities. However, the disease is extremely more than one kind of antibiotic. In large grow-out unsightly and is very problematic for wholesalers facilities antibiotics can be added to diets. See antibiotic treatments below in 7.7 ‘A summary of some common ish medications, in alphabetical
Sporozoa (8 – 100 microns) (Note that sporozoa are classified as protozoa, but are covered separately here due to the differences between them and other protozoa from a fish disease management perspective.)
here are several members of the sporozoan
group which can cause very serious problems in cultured ish, and susceptibility appears to be extensive. However, generally sporozoan diseases are relatively slow to develop, unlike, for example, mouth fungus (Flexibacter columnaris) or white FIG 7.3. Adult neon tetra showing area infected spot (Ichthyophthirius multifilis) which can develop with Pleistophora.
Wissenschaftliche Publikationen in medizinischen Fachjournalen Ernst E, Weihmayr T, Matrai A, Resch KL. Changes in blood rheology of grossly obese individuals during a very low calorie diet. Int J Obes 1989;(Suppl2):167-8. Resch KL, Ernst E, Matrai A, Paulsen HF. Blutfließeigenschaften beeinflussen die Prognose nach Schlaganfall. Perfusion 1990;3:99-110. Resch KL, Ernst E, Matrai A, Schmid
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