936 BULLETIN OF THE BUREAU OF FISHERIES. 



1. Fungus growth developed on sculpins. Investigation showed that there 

 were 50 per cent too many in the tank. The fish, a near-shore, rocky-bottom 

 species, needed maximum aeration; this was increased and in a few weeks the 

 fishes were in the best of condition. 



2. Male sheepshead constantly died because attacked with a virulent fungus ; 

 swam at the surface with the head out of water; showed bruises over body, 

 and lacerated fins. Attendant diagnosed the case as "fish sickness." The 

 habits of the fish were carefully studied, a man watching them even at night. 

 This watcher reported that as soon as the lights went out the largest males 

 attacked the other males furiously and repeatedly bit and lacerated them. 

 The next day two sheepshead tanks were arranged, each with one male to ten 

 or twelve females. In these there was no more difficulty with fungus growth. 



3. Surf -fish were attacked with malignant fungus growth. They were in a 

 tank with air coming up through the bottom, thus receiving the minimum 

 amount of aeration. The surf -fish in California lives near the surf and requires 

 the rush of well aerated water. Surface aeration of a violent kind was provided 

 and the fishes recovered at once 



4. A mysterious illness attacked rock bass. Examination of the tank showed 

 poor sanitary conditions. The fish were invariably overfed, the debris col- 

 lected at the bottom, and the underside of the rocks was covered with " white." 

 Feeding was stopped for several days, a larger per cent of salt introduced, 

 and scavengers — hermit crabs, mollusks of various kinds — were put into the 

 tank. In two weeks the tanks were completely sanitary. 



5. Fish in a standing tank were troubled with fungus growth. It was sus- 

 pected that the evaporation (near sunlight) was too rapid, and fresh water was 

 added, a quart at a time. The fishes recovered, apparently showing the trouble 

 to be too much salt. 



Briefly, I would advocate, instead of elaborate and expensive treatment of 

 fishes, prevention; in other words, a study of the habits of fishes, so that each 

 one kept in confinement may be given the conditions and environment it 

 requires. If this is done, at least in my experience it has so proved , fungus disease 

 need not be dreaded, as it will not appear. 



As to treatment for fungus, however, if the fish is a common one and easily 

 replaced, as trout, remove and destroy it at once and waste no time on it. If 

 the fish is rare and treatment is necessary, remove it to a new tried tank and 

 double or quadruple the aeration from overhead or direct fall. See that the 

 tank has scavengers (crabs) sufficient to keep it perfectly pure and clean. If 

 fungus has developed, take the fish out, using gloves, and wipe the spots with a 

 sponge dipped in a strong solution of salt and water. Stop feeding for a few 

 days; then give the fish its natural food, if this can be determined. 



