///. EXPERIMENTAL FISH EmRYOLOGy 



44. THE CARE AND FEEDING 

 OF LABORATORY FISH* 



SIZE OF TANK: 



This depends upon whether the fish are to be raised in colonies; whether they are large 

 or small, active or sluggish; whether they are sociable; and whether the adults eat their 

 eggs or their young. In general the shape should be rectangular, with the depth and 

 breadth the same and the length twice as great. The most satisfactory size is 8-| x 8| 

 X 16 inches (supplied in quantity by Wil-Nes Co. , 220 E. 134 St. , New York City. ) 

 Such a tank may be used for colonies of Oryzias, Paradise, or Platys, which represent 

 egg-layers, bubble-nest builders, and live-bearers. This size tank may also be parti- 

 tioned off for a Betta breeding tank. Larger tanks will be necessary for Hemichromus 

 or the large mouth-breeders. The fast-moving Zebras do well in a long and narrow tank, 

 measuring 4 x 4 x 24 inches. 



STRUCTURE OF THE TANK: 



Except for the frame, the tank should have walls of glass and bottom of slate or glass. 

 None of the frame should come in contact with the contained water. A glass cover should 

 be provided, which will keep out all dust and reduce evaporation. A corner of this glass 

 plate may be removed in order to facilitate the introduction of the daily food ration. The 

 edge of the glass plate may be protected by adhesive tape, or ground lightly with a metal 

 file. 



REPAIR OF THE TANK: (Generally not recommended for modern tanks) 



When a leak occurs it will be necessary to remove the glass plate on that side, at least. 

 Occasionally all the glass plates should be removed and the entire frame cleaned. This 

 is a tedious performance but a little extra care will reduce the necessity for repetitions. 

 Never move a tank containing water. 



Remove the glass plates in the proper order. When the bottom is glass, it is the first to 

 be removed since it was the last to be put in place. Soften the cement which holds the 

 glass in place by means of a cup of cleaning fluid (Dri-Kleen), and remove the cement 

 and wedge out the glass with a putty knife. Remember that the glass is brittle. Thor- 

 oughly clean the frame and glass before replacing the parts, and cement with regular 

 aquarium cement. 



It is virtually impossible to cover a leak with aquarium cement and to have it hold. Even 

 the slightest leak should be remedied by complete removal of the faulty plate. After a 

 repair job, run water through the tank for several days. 



CLEANING THE TANK: 



Even a new tank should be treated with dilute KMNO^ solution for at least 24 hours before 

 use, and an old tank may occasionally require a complete cleaning (Brine and "elbow- 

 grease" are the best). In such cases a thorough washing with soap and water, a soaking 

 with dilute KMNO4, and a 24-hour rinsing are in order. 



* The author expresses profound appreciation for help in organiziiag this section, particularly from Drs. I. R. Aronson and W. Atz 

 of the American Museum of Natural History, and also their co-workers Drs. Evelyn Shaw, and Phyllis Cahn. 



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