TROPICAL AQUARIU.M FISHES 



210 



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 (% 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 w'hole 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 w-ell 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. 



Fk;. 160. WooDKN Brkedint. Tank 



