448 



U. S. BUREAU OF FISHERIES 



is necessary; or, if preferred, about half the water may be drawn 

 oft' through a siphon and a similar amount of fresh, aerated water 

 added. During very warm weather this will jDrobably have to be 

 done about once a month. If the water should become vitiated at 

 any time, the aquarium must be thoroughly cleansed and the entire 

 water supply renewed, the fish first having been removed to another 

 vessel. When fish become restless and rise to the surface of the 

 water to breathe, it indicates that the oxygen supply in the aquarium 



is insufficient. Relief may be given 

 them by dipping up and pouring back 

 some of the water. 



A small aquarium can not sustain 

 much life. Fishes, like human beings, 

 can not thrive in crowded habitations, 

 and thousands of goldfish have been 

 lost by the overstocking of ac^uaria. 

 The number that can be maintained in 

 healthful condition m a 5-gallon vessel 

 will depend upon its location and shape, 

 the water temperature, character of the 

 plant life, size of the fish, and the 

 amount of light admitted. 



It is better for beginners to start with 

 a few of the hardier varieties of gold- 

 fish until the fundamental principles of 

 aquarium keepings are understood. 

 When common goldfish can be kept 

 with no losses, it is time to branch out 

 and undertake the keeping of the more 

 interesting breeds. 



A well-balanced aquarium of 5-gallon 

 capacity is capable of maintaining 2 

 goldfish, each 2 inches long exclusive of 

 tail, 1 frog tadpole, and 4 snails. One- 

 fourth of the bottom area should be 

 planted with aquatic vegetation, the 

 ends or roots to be embedded from 1 to 

 11/2 inches in the sand or gravel, and the 

 plants evenly distributed over the en- 

 tire surface to admit light and provide 

 for the free movement of the fish. In 

 choosing the snails, select species that 

 do not feed on plants. The best ones 

 are the Planorbis and Vivipara. Snails 

 help to keep down the growth of alga?, 

 while the tadpole acts as a scavenger, consuming all waste matter in 

 the aquarium. "Wlien about to enter the frog stage the tadpole must 

 be provided with a resting place on the surface of the water ; other- 

 wise it will drown. In a 5-gallon aquarium two handsome specimens 

 of fringe-tail goldfish will make a fine appearance. Once or twice a 

 week the inside surface of the front glass should be cleaned to pre- 

 vent obstruction of the view by accumulations of algse. For this 

 purpose a flat sponge or piece of felt attached to the flattened end of 



Fig. 3. — Willow moss (FontinaUs 

 antipyratica) . Natural size 

 fairly good oxygenator 



A 



