THE AQUARIUM AT THE WORLD'S COLUMBIAN EXPOSITION. 155 



experiment tried with water from the lake, from the lagoon, and from the central pool 

 in the aquarium building, and a large proportion also of those tried with vials of water 

 from the aquaria and from the supply pipes inside, yielded cultures of this Saprolegnia. 



The principal safeguards and remedial measures against this fungous disease are 

 (1) the original discrimination of susceptible from hardy species of fish, that each 

 may receive its appropriate care and treatment; (2) the utmost care in the capture, 

 handling, and transportation of fish intended for the aquarium, that they may arrive 

 without bruises or loss of scales, and (even more important than this) without unnec- 

 essary weakening of their vitality; (3) the use of a large shallow pool as a temporary 

 receptacle for new arrivals, where they may be kept under surveillance and under the 

 most favorable conditions until any tendency to fungous disease may have declared 

 itself; (4) the rejection, or at least the separate maintenance, of all injured speci- 

 mens until death or complete recovery; (5) the maintenance of a hospital tank to 

 which all individuals may be immediately removed for special care and treatment on 

 the first appearance of fungous parasitism in any tank; (6) the use of open shallow 

 tanks (in place of deep aquaria) with light-colored bottoms, freely exposed to sun and 

 air, and the maintenance of a free and rapid flow of water through them; (7) the 

 association in the same tank of fishes of different habit, but especially the distribu- 

 tion everywhere of suckers, buffalo, or other bottom feeders, which continually police 

 the tanks by working over the bottom for particles of food; (8) the most scrupulous 

 cleanliness in the management of the tanks, and care not to introduce a superabund- 

 ance of food; (9) the thorough filtering of the water, preferably with the aid of alum 

 so added that there shall be no excess remaining; (10) the prompt and thorough dis- 

 infection, by washing and soaking with a solution of carbolic acid, of every tank in 

 which the fungus appears; (11) the use of a solution of salt or carbolic acid as a 

 remedy for moderate cases of disease; and finally (12) an abundant food supply aud 

 expert care generally in the maintenance of the health and vigor of the fish. For this 

 last purpose I am inclined to suggest the establishment of an exercise pool for the 

 larger and more active species, especially the game fishes, which might thus be 

 released occasionally from their cramped quarters in the aquarium and permitted to 

 stretch their muscles in a good straight swim. 



1 hardly need say that in handling diseased specimens special nets should be 

 used, which should then be considered as infected and should never be allowed to 

 touch healthy fish or be put into the water with them until soaked in some disinfec- 

 tant solution. I may add that the source of the water supply may easily have an 

 important bearing on the liability to fungous disease. If derived from clean springs 

 or wells, or perhaps even from clear running streams, the water will contain few or 

 none of the spores of Saprolegnia, since this fungus grows normally and most abun- 

 dantly on decaying organic substances. It would further seem a good general practice 

 in establishing a fresh-water aquarium, to select ouly young or half-grown specimens 

 as representatives of the more susceptible species, since these commonly resist the 

 fungus far better than adults, and might be expected to become in time much better 

 adapted to aquarium life. 



Although there is a general impression that this fungous disease will not attack 

 healthy fishes unless offered a starting-point in some surface injury, it is now certain 

 that this is not true. The general current of our observation during the season 

 leads to this conclusion, which has been amply confirmed by a special experiment 



