TROPICAL AQUARIUM FISHES 219 
forms ought to be soaked with water just before using, or else thoroughly 
paraffined. Cement mixture should be wet enough to just pour, and 
needs to be well tamped to avoid bubbles. Re-inforcement rods (%4 inch 
diameter) are essential, especially around the top edge, where a con- 
tinuous band should be formed. Over the bottom the bars should be 
wired together, forming 4-inch squares. Do not be in a hurry to get the 
forms off. The whole job should be moistened for a day and allowed to 
stand for two more days if their removal is going to cause any Strain. 
Glass must not be embedded directly in the concrete, but provision made 
for later setting it in with ordinary aquarium cement. If sides do not 
support the glass evenly they should be cut away or built up until they 
do. Otherwise glass is sure to crack when the soft aquarium cement 
yields to the water pressure. After base is finished it is well to paraffine 
it as described on page 216. All cement pouring should be done at one 
operation. 
CONSTRUCTION OF WOODEN TANKS 
Many expert fanciers are of the opinion that for the welfare of fishes 
there is no receptacle equal to a well-seasoned wooden tank. For breeding 
purposes they are especially valuable, but in no case should tanks be used 
before numerous changes of water have been made over a period of 
several weeks. 
Fic. 160. Wooven Breepinc TANK 
