AQUARIUM MANAGEMENT 17 



should be brought to about 6.8 by use of acid sodium phosphate. 

 Alkaline conditions are produced by using washing soda. The highest 

 reading (alkaline) should not exceed 7.4. The chemicals mentioned 

 should be used only in conjunction with a testing set— never by guess- 

 work—especially the soda. See also page 95. An equal mixture of 

 plaster of Paris and precipitated chalk made into a thick paste in 

 water, hardened and broken into small lumps is a slow neutralizer of 

 acid conditions. About a shellbark-size piece to ten gallons. 



Testing sets are advertised in the various aquarium magazines. 

 They are sometimes of value in testing the water which is proposed for 

 aquarium use, especially where highly alkaline "hard" artesian or well 

 water needs to be neutralized. 



Sick Fishes. It is always safer to remove an affected fish from the 

 others. If the trouble is a contagious one, the aquarium or tank should 

 be thoroughly disinfected, not overlooking the plants in this matter. For 

 all practical purposes they can be sterilized by placing for one hour in a 

 permanganate of potassium solution, 3 grains by weight to the gallon of 

 water. Satisfactory results will also be given by dipping plants for a 

 few moments in concentrated lime water, or in household ammonia, re- 

 duced to one-fiftieth strength. Either of these methods should be ap- 

 plied to all new plants introduced into the aquarium, especially those col- 

 lected from the wild, or from aquaria of doubtful condition. In case of 

 an aquarium becoming contaminated, it can be disinfected by dissolving 

 in it permanganate of potash to the strength already indicated, allowing 

 it to stand from two to three hours, first removing all mussels, snails and 

 fishes. In changing to clear water again it will do no harm if a little 

 permanganate remains. 



Unless newly acquired fishes come from a source beyond suspicion 

 it is a grave risk to introduce them at once into an established aquarium 

 of healthy fish stock. They really should first be quarantined and care- 

 fully observed for at least two weeks, this being particularly true of im- 

 ported goldfishes. They may already be inoculated with diseases only in 

 process of incubation, but which will nevertheless develop. 



Care of Fish Nets. It is a safe practice after using a fish net to al- 

 ways rinse under a tap of clear water. The germs of fish diseases and 

 the spores of green-water algae which might later infect another aquarium 

 are thus eliminated. It might be added, for the reassurance of any who 

 need it, that no fish disease can be communicated to a human being by 

 contact. 



Scavengers. These are natural agencies for getting rid of most of the 

 harmful offal and decomposition in the aquarium. They consist largely 

 of those species of snails that do not attack the plants. Among the best 



