MAKING OUR HOME BEAUTIFUL 213
The idea is still prevalent, born of the old days of fish globes and persisting through ignorance, like many other exploded notions, that the aquarium requires a vast amount of time and fussing, and especially that the more frequently the water is changed the better it will be for the animal life. Nothing could be farther from the truth, for when a balance is secured the less changing of anything the better it will be, for fear of disturbing the nice adjustment which Nature has set irp and the zvater should not be changed at all. Yet anyone maintaining a balanced aquarium will agree that the question first and most frequently asked by the interested visitor is, "How often do you have to change the water?"
The balance of plant and animal life means complete and continual ventilation. Not only is oxygen supplied in sufficient quantities by the plants, but the carbon dioxide given off by the animals in respiration is consumed by the plants in the process of starch making. The adjustment is Nature's own, and all animals are adapted to it. Such an arrangement is a pond in miniature and may be used in the scientific study of aquatic life of various kinds. In the majority of cases, to be sure, only goldfishes are kept, in addition to a few tadpoles or snails and plants. According to the interests of the aquarist, however, this may be varied indefinitely. Many other attractive exotic fishes of striking colors, form, and habits may be readily secured from dealers, or the collector may take up the study of local native fishes, the natural history of which will be found no less interesting than that of the exotic species.
Aquatic insects afford a most interesting and almost infinitely varied field for study, and their habits, metamorphoses, etc., may be most readily investigated by this means. Again, if the aquarist is interested in aquatic botany, he will find here excellent opportunities and means for studying many water plants. Marine life is even more varied than that of the fresh-water, and endless opportunities are afforded to those who live within reach of the sea. The microscopist will also find a constantly changing and ever interesting field of research in the minute life of the aquarium.