20 MARVELS OF FISH LIFE 
white patches are patches of Saprolegnia ferar. Fungus 
attacks fish when they are weak and unhealthy, and 
the cause of the trouble is usually to be found in 
want of cleanliness, in insufficiently oxygenated water, 
and in want of shade for the fish. To treat fish when 
attacked, if the trouble has not gone too far, is not 
difficult. Dissolve two or three handfuls of common 
salt in a bucket of water, and let the diseased fish swim 
about in this until they turn on their backs. Revive 
them in fresh water, and repeat the process two or three 
times, and for the future keep them in healthy surround- 
ings. 
Big patches of fungus may be treated by swabbing 
with a strong solution of Condy’s fluid, and a lump of 
rock salt occasionally placed in the tank or aquarium 
is a deterrent to fungus. Above all, the woodwork must 
be charred or painted, otherwise fungus is sure to appear. 
