114 GOLDFISH VAEIETIES A]^D 



For chemical reasons the salts should each be dissolved sepa- 

 rately and enough water finally added to make ten gallons. Any good 

 drinking water will do to mix with, although distilled water is not to be 

 recommended because of its total lack of mineral content. Turk's Island 

 salt is evaporated seawater and has been successfully used by the Govern- 

 ment at Washington, In mixing this or in preparing the foregoing arti- 

 ficial water, the final test for strength should be by hydrometer as previ- 

 ously directed. As chemicals vary in strength and in weight owing to 

 different degrees of moisture, the hydrometer used in solutions of about 

 60° Fahrenheit furnishes the only accurate gauge. 



Newly made artificial marine water ought not be used for several 

 days, but be given a little time to ripen. An occasional stirring helps the 

 process. 



Cleaning Marine Water. It is desirable to keep the marine aquarium 

 crystal-clear, both for the benefit of the inmates and the pleasure of the 

 observer. To this end several factors must be borne in mind. Start with 

 clear water. Do not overcrowd nor overfeed. Use only subdued light. 

 Quickly remove decaying plants, dead mussels, anemones, etc. Occa- 

 sionally siphon off the bottom (see page 229) and after setting, pour back 

 the clear water or return through filter. Very little loss of water is occa- 

 sioned if the dregs are thrown away after water has settled, particularly if 

 a tall jar is used. The filter arrangement described on page 233 is very 

 desirable for the marine aquarium. The more pretentious establishments 

 run the water oft' into deep filter-beds of fine sand, squirting it back into 

 the aquarium under pressure to increase oxygenation. This, next to run- 

 ning seawater, is the ideal arrangement, but is out of reach of the ordinary 

 mortal. 



Temperature. This matter depends very largely upon the climate 

 from which the aquarium inhabitants come. For this reason it is not well 

 to mix animals of tropical and temperate zones. Many of the tropical 

 fishes come north in summer and can successfully withstand a temperature 

 of 62° F., but in the confines of an aquarium they will not prosper in the 

 lower temperatures required by the fishes of our own climate. Tropical 

 fishes are happy in a temperature ranging from 68° to 75°. Some of them 

 can succeed when it is even warmer, but it becomes difficult to satisfac- 

 torily oxygenate the water. 



Fishes and other marine animals of the temperate zone prefer a range 

 from 55° to 68°. It will be noted that the tropicals and temperates meet 

 at 68°, so if the attempt is made to mix them, this is the temperature that 

 should be closely adhered to. 



