Ornamental fish keeping is one of the most
popular hobbies in the world. The aquarium fish trade has a turn over of 5
billion US dollars and an annual
growth rate of 8%. India
Disease has become a critical
factor hampering the development of ornamental fish culture in many countries. Diseases
of ornamental fishes are caused by parasites, fungi, bacteria and viruses.
The most commonly observed
viral disease of ornamental fishes is called Lymphocystis disease.
This disease is caused by an iridovirus, which infects connective tissue cells
of the fish.
The majority of bacterial
infections are caused by gram-negative organisms such as Aeromonas, Citrobacter,
Edwardsiella, Flavobacterium, Mycobacterium, Pseudomonas and
Vibrio. The majority of bacterial fish patogens are natural inhabitants
of the aquatic environment. Over 805 of the gold fish contained Pseudomonas,
Citrobacter and Escherichia.
Among fungi, Saprolegnia is the mot
common genus affecting tropical fishes. The protozoan diseases include white
spot disease, hole in the head disease, itch disease, neon tetra disease and
guppy killer disease. Both monogenean and digenean trematodes parasitize
tropical fishes. The important crustacean parasites of tropical fish include ‘anchor
worm’or ‘fish louse’ and some isopods. The keys to minimize disease outbreaks
in a fish farm are maintenance of good water quality, proper nutrition and
sanitation. Disease treatments should never be applied in a haphazard fashion.
When needed, chemical or antibiotic treatment should be targeted at a specific
problem.
