102 THE GOLDFISH AND ITS CULTURE. 
microscope, reveals a number of parasites darting about hither and 
thither across the field of the instrument, These minute organic 
bodies, technically termed dacteriz, resemble a wood-tick in general 
shape. They appear to eat into the skin of the fish, destroying that. 
structure, and in consequence interfere very much with the function 
the skin performs in throwing out poisonous substances that form in 
the tissues inside. The beautiful colors of the fish disappear from 
the tainted parts, they becoming quite black. The result of the 
disease is the death of the fish. 
When afflicted with the trouble, the fish can be observed rubbing 
itself against the plants, the rocks, or in the sand upon the bottom of 
the aquarium. 
The cause of the disease may be found in the usual over-feeding, 
in which case the remnants of food remain in the water until decom- 
position sets in. The temperature not being favorable for the pro- 
duction of water-purifying insects, the Jacterie make their appearance 
greatly to the detriment of the fish. 
The name ‘‘slime” has heretofore been applied to this description 
of disease, but without any apparent reference to the cause producing 
the trouble. In the author’s opinion, it is the presence of the para- 
sites that makes the whole difficulty. They annoy the fish by their 
presence, their attacks upon its skin setting up an increased flow of 
blood to the part upon which the thick coat of slime is found. 
Manifestly the best method of treating the disease is the removal, or 
rather the prevention, of the cause, for if the dacterie are not allowed 
to develop, they of course can do no harm. 
Tadpoles and snails should be put into the aquarium to consume 
any remaining particles of food, and the feeding itself more carefully 
attended to. Place the aquarium in a warm and light location, 
adding to the water a pinch of table-salt when filling the vessel. 
