TROPICAL AQUARIUM FISHES 151 



tions are a swelling of the body and the scales standing out at an angle, 

 producing a ruffled appearance. 



Treatment. No cure is known for dropsy in fishes. They have been 

 known to improve in an outdoor pool in summer, but on the approach of 

 cool weather the symptoms returned with increased severity, death follow- 

 ing as usual. There is a current belief that a few drops of digitalis in the 

 water sometimes effects a cure. The author has never been able to verify 

 a single such case. If the fish is valuable, its life may be prolonged by 

 "tapping" it. This is done by inserting a fine needle beneath the skin, 

 holding needle nearly flat to the body so that it again emerges in about a 

 quarter inch. After repeating this at a number of points, enough liquid 

 can be drawn off to relieve the fish, w^hose health and spirits do not seem 

 to be particularly affected until shortly before death. The operation can 

 be repeated when necessary. 



Swimming Bladder Trouble. As before stated, highly bred, short 

 bodied fishes are the more susceptible to this not uncommon disorder. 

 Sometimes the victims are unable to rise from the bottom except by a 

 violent effort, or again they may lie at the top of water at an angle, or even 

 upside down. Scaleless varieties are the more susceptible, particularly the 

 light colors. Reduced temperatures, even when brought about slowly, are 

 responsible for most cases. 



Treatment. No cure for swimming bladder trouble is known, but it 

 is sometimes relieved by placing in very shallow^, slightly salt warm water. 

 If the fish is benefited it will always have to be kept in temperate water, 

 preferably shallow. 



It should be borne in mind that not all cases of loss of equilibrium 

 are due to bladder trouble, but may be caused by accumulated gases result- 

 ing from indigestion. Treatment for constipation will relieve these cases, 

 but such fishes will have to always be watched carefully thereafter. 



Gill Congestion. There are two forms of gill congestion. The most 

 important, generally known as "gill fever," is that attacking fry from two 

 to five w-eeks old, and is easily responsible for more losses among gold- 

 fishes than all other causes combined. The gills become inflamed and 

 swollen, presenting a distended appearance. Owing to the minuteness of 

 the fish at this period a further observation is difficult except wath a mag- 

 nifying glass, w^hich shows white threads like bristles sticking from the 

 gill plates and openings. The disease is highly contagious, so that if one 

 affected fish is found in a thousand, it is very difficult to save any of them, 

 even though the sick fish be removed at once. 



The other form affects mainly young fishes about 2 inches long. The 

 gills swell rapidly, the infection spreading to the throat and producing a 



