844 



ZOOLOGICAL SOCIETY BULLETIN. 



STICKLEBACKS. 

 These miniature fishes are found both in fresh and salt-wal 

 habits are especially interesting. 



tity of animal life during the day and in bright 

 weather than it will at night or on dark days. 

 The animal life of the standing aquarium must 

 therefore be regulated to meet the poorest rather 

 than the best conditions of oxygen production 

 by the plant life. 



Temperature also affects the rate of starch 

 making and consequently of oxygen elimination, 

 as the protoplasm of the plant is more active 

 in a higher than in a lower temperature. How- 

 ever, the fishes are also less active in colder 

 water and consume less oxygen, so that these 

 factors balance each other and temperature does 

 not especially affect t h c 

 aeration of the aquarium. 



THE AQUARIUM TANK. 



Undoubtedly the best kind 

 of a receptacle for the be- 

 ginner is the oblong, 

 straight-sided aquarium with 

 metal frame, glass sides and 

 slate bottom. The medium 

 size, holding six or eight 

 gallons, will be the best for 

 the beginner. The smaller 

 sizes are difficult to balance 

 and tlie larger ones are more 

 expensive. For larger aqua- 

 ria, eight gallons and up- 

 ward, it is the only type that 

 can be used to advantage. 

 When well set up such a 

 tank will last for years with- 

 out leaking, and is easily 

 reset, or can often be read- 



ily mended by running a lit- 

 tle asphaltum or an aquar- 

 ium cement in the joints. 

 The rectangular, straight- 

 sided, all-glass jars are ex- 

 cellent; better in some re- 

 spects than those with metal 

 frames, for they are not 

 likely to spring a leak. 



The glass jars, however, 

 are more likely to crack and 

 so prove an extra expense, 

 but in the hands of the ex- 

 perienced aquarist they are 

 perhaps the most satisfac- 

 tory for sizes under five gal- 

 lons. Care should be taken 

 to see that such jars rest 

 firmh' and evenly upon their 

 Their nesting bases, and that they are not 



subjected to sudden changes 

 of temperature. The cylin- 

 drical jar with straight vertical sides is satisfac- 

 tory to maintain, but the inmates appear some- 

 what distorted througli the curved sides. For 

 smaller aquaria the ordinary battery jar is as 

 good as anything, except for the distortion, and 

 has the advantage of being cheap. Very beauti- 

 ful and well balanced aquaria can often be made 

 with the two-quart size, but these are suitable 

 only for very small animals and few of them. 



To test the limits of the capacity of the two- 

 quart size, the writer once kept in such a jar, 

 with plenty of weeds and in good light, a carp 



YOUNG TAUTOG. 

 nteresting fish for It 



