ZOOLOGICAL SOCIETY BULLETIN. 



851 



For removing inanimate objects from the 

 aquarium or for readjusting them, a strong pair 

 of wooden forceps is advisable. The hands 

 should not be put into the water and on no ac- 

 count should the fishes be taken into the hands. 

 If it becomes necessary to remove the fishes a 

 small net of cheesecloth should be employed, and 

 great care should be taken not to injure them by 

 loosening their scales, as any such abrasion of- 

 fers a foot-hold to the deadly fish fungus (Sa- 

 prolegnia). 



MARINE AQUARIA. 



As most of what has been said of the fresh 

 water aquarium will apply with equal force to 

 the salt water aquarium, a detailed account will 

 not be necessary. The factors governing life 

 are the same in both. The best plants for aerat- 

 ing are the species of green algae known as sea- 

 lettuce. The common broad-leaved form is usu- 

 ally best arranged by floating at the surface by 

 a few small pieces of cork in such a manner that 

 portions of the leaves will extend downward into 

 the water. The species of marine plants are 

 numerous and the various red, green and brown 

 forms with strap-like or with finely divided 

 fronds may be placed at the bottom to give va- 

 riety and color, as well as to aid in aerating the 

 water. Very often pebbles with these plants 

 attached may be secured in shallow water. 



Unfortunately the salt water aquarium is a 

 practical impossibility for most persons who are 

 unable to make occasional visits to the shore. 

 Artificial sea water can be easily prepared at a 

 trifling expense, if the formula of Gosse is fol- 

 lowed: chloride of sodium (common table salt) 

 eighty-one parts, chloride of potassium, two 

 parts, chloride of magnesia, ten parts, sulphate 

 of magnesia (Epsom salts) seven parts, total 

 100 parts. A pound of this mixture is sufficient 

 to make about three gallons of artificial sea 

 water. It should be filtered before placing in 

 the aquarium. 



To be sure, natural sea water contains many 

 other salts, but they have been found unneces- 

 sary for the animal life of the aquarium and may 

 be neglected. The sea water part of the prob- 

 lem is thus readily solved, but very little ma- 

 rine life is ever handled by dealers in this coun- 

 try and the difficulty of obtaining animals and 

 plants renders the salt-water aquarium impract- 

 icable for the person of average means who lives 

 at a distance from the sea. 



To one who is within reach of the sea, how- 

 ever the marine aquarium offers a never ending 

 and ever varied field for study and investiga- 

 tion. Animals and plants may be obtained the 

 year round, and many of them live well within 



the restricted limits of the aquarium. The many 

 species of hydroids and sea anemones, marine 

 worms, bryozoans, mollusks of many kinds, 

 crabs, shrimps and other crustaceans, sea squirts 

 or ascidians, as well as fishes are to be obtained 

 and give a variety to the miniature scene which 

 cannot be paralleled in the fresh water aquarium. 

 Some of the small aquaria at the New York 

 Aquarium have been maintained in a balanced 

 condition for several years — one for as long as 

 twelve years. Of course both animals and 

 plants have been occasionally added to the stock, 

 but the balance has not been interfered with dur- 

 ing that time. Fresh water in small quantities 

 must occasionally be added to the marine aquar- 

 ium to replace that which evaporates. The ad- 

 dition of sea water would, in the course of time, 

 cause the salinity to become too great, since the 

 salts do not evaporate. 





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IMPLEMENTS OF USE TO THE AQUARIST. 



