204 



THE GUIDE TO NATURE. 



The Household Aquarium and Its 

 Inmates and Management. 



Part I. 

 The keeping of an aquarium with 

 its living plant and animal inmates is 

 an esthetic pleasure not equalled by- 

 other easily obtained and inexpensive 

 means. Land plants and animals are 

 interesting, but they do not offer the 

 continual fascination of this glimpse of 

 fluvial life, which when properly ar- 

 ranged is a beautiful, ever-varying liv- 

 ing picture and the handsomest orna- 

 ment of the household. 



Success with the aquarium depends 

 upon an understanding of the simple 

 principles of aquatic existence, most 

 failures being due to a lack of this 

 knowledge. It is really the pond or 

 pool in miniature, and to achieve suc- 

 cess these conditions must be repro- 

 duced. 



Only in comparatively recent times 

 has this been understood. In 1833 

 Priestly discovered that growing plants 

 gave off oxygen ; in 1844 Ward suc- 

 ceeded in keeping fishes together with 

 plants in Stillwater aquaria ; in 1850 

 Warrington published his observations 

 on the" inter-relation of vegetal and 

 animal life; and in 1856 Gosse estab- 

 lished the necessity of scavengers, and 

 so solved the problem of the properly- 

 balanced or self-sustaining aquarium. 



In the breathing of the aquatic fauna 

 a considerable quantity of air is ab- 

 sorbed, required for the oxidation of 

 the waste carbonaceous matter, pro- 

 ducing carbonic acid gas; which, in the 

 presence of sunlight, is absorbed by 

 the plants, the contained carbon being 

 required to add to their solid structure 

 and the thus purified oxygen liberated 

 into the water to sustain the living 

 creatures. By this double action of 

 plants and animals an almost perfect 

 balance is sustained, the animals dimin- 

 ishing the oxygen and adding to the 

 carbonic acid gas, and the plants 

 diminishing the carbonic acid gas and 

 adding to the oxygen. 



Hence if plant and animal life is 

 present in correct proportion, the qual- 

 ity of the water is only disturbed by 

 the presence of other elements pro- 

 duced by the decomposition of organic 



matter, dead animals, decaying plants, 

 excrement and uneaten food ; and to 

 check this deleterious change molluscs 

 and other scavengers are required. 

 With this necessary law of aquatic ex- 

 istence in mind, together with careful 

 feeding and good daylight, nearly the 

 whole difficulties of aquarium keeping 

 are solved. 



Artificial aeration for the fresh- 

 water aquarium is not required in the 

 presence of a vigorous plant growth, 

 but marine plants are lower forms, the 

 Cryptogams, all inferior generators of 

 oxygen, and some such means is im- 

 perative for the marine or salt-water 

 aquarium. 



In establishing an aquarium any 

 water-tight receptacle will serve, but 

 the larger its contents the better will be 

 the results. Its form should be such 

 as to admit of large surface aeration. 

 Glass receptacles have the advantage 

 that their contents may be more easily 

 observed, but the ordinary fish globes 

 are the worst of all forms. All-glass 

 vessels are too liable to fracture by the 

 pressure of the water, by expansion and 

 contraction, and by accidents. The 

 brass or iron framed glass aquarium 

 with slate bottom is the best and its 

 form should be that of a double cube, 

 which for the novice may be 32 inches 

 long, 16 inches wide, and 16 inches 

 high, and for the experienced aquariist 

 48 by 24 by 20 inches or larger. 



It should be placed upon a table or 

 stand facing either a northern or north- 

 eastern light in the summer and in the 

 winter where it will receive a few hours 

 of the morning sunlight. The light 

 should be principally on the surface of 

 the water and be such that it will not 

 materially change the water tempera- 

 ture. Too strong is as injurious as too 

 little light. 



Any drinking water will serve for the 

 fresh-water aquarium, as the fishes 

 usually kept are those of the pond or 

 slow-flowing stream, but for those of 

 cold-water brooks attention must be 

 given to both its character and temper- 

 ature. This will be treated of here- 

 after. 



In installing an aquarium the first 

 important consideration is the proper 



