10 



Aquatic JLitt 



the aquarist who wants to keep his old 

 water as long as possible, and that means 

 for years, it becomes a matter of plain 

 mathematics to predict when he will 

 have a salt water aquarium. I concede 

 that salt has its place, especially with 

 such of our pets as normally inhabit 

 brakish water, and I can see no partic- 

 ular objection to using a trifle when es- 

 tablishing a tank, but as a rule its use- 

 fulness ceases here. The aquarist should 

 have very cogent reasons for adding 

 it periodically, else he may start some- 

 thing he can't stop, short of renewing 

 his water entirely, to the detriment of 

 his fishes. 



It is unfortunate that the very things 

 that are most potent in disqualifying 

 water for aquarium purposes happen to 

 be invisible to us when present, though 

 the odor omitted may afford us a clue 

 to the degree of saturation with obnox- 

 ious gases. The apparently normal con- 

 dition of his water, as judged by the eye, 

 may easily lead the aquarist astray in 

 searching for the true cause of the low- 

 ered vitality of his more sensitive fishes. 

 Visible derangements of water, though 

 as a rule harmless to aquatic life, are far 

 more apt to be corrected promptly by 

 the caretaker, because these always ren- 

 der aquaria unsightly. Green turbidity, 

 caused by an over-abundance of min- 

 ute algae, is in itself not nearly as ob- 

 jectionable to fishes as the strong light 

 that developed it, especially if this hap- 

 pened to be a side light. Under natural 

 conditions light falls from above, there- 

 fore only reflected light strikes the eyes 

 of fishes. Intense side light on an aquar- 

 ium should be softened, if for no other 

 reason. 



A slightly milky appearance of new 

 water a few days after fishes have be- 

 gun to live in it, may be taken as proof 

 that it contains no strong acids. The 

 disturbanace is effected by the precipita- 



tion of previously soluble calcium salts 

 (hard water), the carbon dioxide exhal- 

 ed by the fishes acting as the reagent. 

 The water soon becomes clear again. 

 Another sort of discoloration is produced 

 when animal matter, such as unconsum- 

 ed food, dead fishes, snails, etc., remain 

 in the water for a time. This state of 

 affairs becomes dangerous, the water be- 

 coming charged with the products of de- 

 composition, mostly gases again, that are 

 so harmful to all higher forms of life. 



Although it is important for the owner 

 of freshwater aquaria to avoid frequent 

 change of water, it is still more so in the 

 case of marine aquaria. Yet all salt- 

 water life, especially the pelagic forms, 

 is exceedingly sensitive to water that has 

 become polluted or unbalanced in mineral 

 composition. Most animals from the 

 Baltic or Mediterranean Seas will quick- 

 ly succumb when placed in water from 

 the North Sea, yet the difference in 

 salinity between these waters is only 

 about one per centum. To aggravate our 

 difficulties some forms of marine life 

 naturally discharge their feces in the 

 form of a muddy cloud, against which 

 no mud-lever yet designed is of any 

 avail. While a sea water aquarium in- 

 land is quite a rarity today, it is perfect- 

 ly safe to predict that the time is not 

 far off when many of our more exper- 

 ienced friends will try their skill on this 

 interesting subject, and then, if it was 

 never brought home to them before, they 

 will learn to appreciate the importance 

 of keeping aquarium water in a highly 

 sanitary condition, and this without al- 

 lowing its mineral character and density 

 to change in the least degree. 



To purify water that has become pol- 

 luted, turbid or discolored by any or all 

 of the reasons enumerated, or through 

 any other sources, there is nothing bet- 

 ter than charcoal filtration. I have con- 

 structed a filter of this kind that is espe- 



