AILMENTS AND DISEASES 



RoTiFERA OR Parasitic Rotifers. Three genera of Rotifera, Al- 

 bertia, Balatro and Dictyophora are parasitic on the freshwater fauna. Some 

 of the already described forms must not be mistaken for this group, whose 

 occurrence on the Cyprinidse is not common. Many parasites are design- 

 ated as "Rotifers" by the fish-culturists,but belong to much lower orders, 

 or are larval forms differing in appearance from the adults. 



Prevention of Parasitic Diseases. The best preventive measures 

 against parasites in the aquarium are care in not introducing them upon fishes 

 and plants and guarding against their spreading by constant vigilance. A 

 careful examination of every newly acquired fish should be made; the 

 appearance of the surface and gills, the condition of the fins and the 

 manner in which they are carried, the behavior of the fish and its general 

 condition noted. Newly acquired fishes should be quarantined at least a 

 week and aquatic plants inspected and carefully cleaned before either are 

 put into the aquarium. A microscope examination of anything suspicious 

 is also advisable. Infected fishes should be placed in the most salubrious 

 surroundings, with a plentiful plant growth, abundant aeration, and nutritive 

 food given. 



An already mentioned sometimes effective remedy is to place the af- 

 fected fishes, or any subjected to contagion, in water taken from neglected 

 out-of-doors tanks which has become very green with algae and other low 

 forms of plant and animal life. This is worth a trial as beneficial results 

 often follow; but if the afflicted fishes are not of value, and their disease 

 does not yield to the remedies before and hereafter mentioned, their destruc- 

 tion is advised. The most rigorous sanitary regulations are required in 

 the infected aquaria or tanks, to destroy every trace of parasites. 



Parasiticides. An absolute means of destroying fish parasites has not 

 yet been found, though acid and alkaline substances have proven beneficial 

 and have effected cures. They destroy the free-swimming parasites but 

 have not been as successful with those burrowing in the skin or in the gills. 

 Solutions which would destroy these are oftentimes fatal to the fishes prior 

 to exterminating the parasites. German ichthyological authorities recom- 

 mend the following remedies, all of which require close attention in their 

 application: 



Two grams of salicylate of soda are to be dissolved in one litre of 

 warm water and permitted to cool. Two vessels, holding about three 

 gallons each, are required; one filled with well-aerated water, of the same 

 temperature as that to which the fish has been accustomed, the other con- 

 taining I yi gallons of the same water. These should be prepared early 

 in the morning and the fish introduced into the partly filled one, after 

 which small even quantities of the solution are to be added at frequent 



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