
AILMENTS AND DISEASES 

Rotirera ork Parasitic Rotirers. Three genera of Rotifera, 4/- 
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 Cyprinidz 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 1n 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 alge 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. 
ParasiticipEs. 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 1% 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 
159 
