28 MAINTAINING FISHES 



much cheaper epoxy paint recommended above for 

 concrete may also be suitable for wooden tanks. Re- 

 gardless of tank size, % inch plywood is best. Joints 

 should be carefully fitted and held together with res- 

 orcinol glue and brass nails or screws. 



METAL tanks: For a number of years the au- 

 thor has used galvanized stock watering tanks for 

 holding larger fishes. They are inexpensive, available 

 in a variety of sizes, and may be easily moved or 

 stored. An overflow pipe may be installed (prefera- 

 bly in the center of the tank) to permit continuous 

 flushing. The zinc coating of these tanks is toxic to 

 fishes, and the tanks should be painted prior to use. 

 As a preliminary to painting, new tanks should be 

 treated with glacial acetic acid and then flushed. Un- 

 fortunately, the author cannot recommend a paint for 

 metal tanks that has proven entirely satisfactory. Cur- 

 rent tests indicate that butyl roofing paint and the 

 epoxy paint recommended for concrete may be satis- 

 factory. 



TEMPORARY TANKS: For short experiments re- 

 quiring large or unusually long tanks, it is possible to 

 use a wooden box lined with six mil polyethylene. 

 Since polyethylene is inexpensive and the frame may 

 be made of scrap lumber, even large tanks can be 

 built at nominal cost. 



