446 



U. S. BUREAU OF FISHERIES 



SUITABLE FORM OF AQUARIUM 



Because of its narrow neck the so-called fish ^rlobe is not adapted 

 to keepino; goldfish in a comfortable and healthy state, its small 

 amount of water surface not permitting the process of absorption 

 of air on a scale sufficient for the well-being of the fish. Another 

 objectionable feature of the globe lies in its reflection and refraction 

 of light rays, which tends to make the fish nervous and uneasy. An 

 aquarium with straight sides is the most suitable for goldfish. It 

 should be of rectangular shape and of equal width at the top and 

 bottom. The rectangular batteiy jar, which may be purchased in the 

 6-gallon size, will give good results. The depth of water should be 

 about the same as the width of the aquarium, and the bottom should 



be covered with clean 

 sand and gravel to the 

 depth of 11/^ inches. 

 Ordinary washed sand 

 and pebbles are best for 

 this purpose, as the more 

 desirable aquarial plants 

 draw most of their nour- 

 ishment from the water 

 and require merely an 

 anchorage. In order to 

 insure an abundant air 

 supply, plants of high 

 oxygenating powers 

 should be selected for 

 the aquarium. 



SUITABLE AQUARIAL 

 PLANTS 



Among the most suit- 

 able plants for an aqua- 

 rium are anacharis and 

 fanwort, also known as 

 Elodea and Philotria. 

 Anacharis, Anacharis 

 canadensis gigantea (fig. 

 1) is a good oxygenator 

 and at the same time 

 provides forage for goldfish. Fanwort, Cahornha carolimana (fig. 

 2), is a very hardy species and thrives well in small aquaria. It 

 is evergreen, will grow from cuttings, especially the forked joints, 

 and a branch planted in the sand at the bottom of an aquarium 

 will produce roots. These plants are vei-y common, and supplies 

 can usually be purchased from goldfish dealers.^ Other desirable 

 aquarial plants are willow moss, Fontinalis antipyratica (fig. 3), 

 and arrowhead, Sagiftaria natans (fig. 4). Very beautiful aquatic 

 gardens may be made by a proper selection of plants. A fre- 

 quently used and very hardy and beautiful plant is the hornwort, 

 C eratophyUuin demersum (fig. 5), but it requires careful attention, 

 as it is liable to decay and contaminate the water. Moreover, it is 



Fig. 1. — Anacharis {Anacharis canadensis fiigantea). 

 One-half natural size. A good oxygenator ; grows 

 rapidly ; thrives with or without roots when set in 

 pebbles or sand ; may be purchased of dealers. This 

 is considered the most satisfactory plant for the 

 amateur aquarist 



