318 U. S. BUREAU OF FISHERIES 



In siphoning water from the bottom of the aquarium to clear off 

 sediment or refuse the water should be saved and strained back. 

 The supply of water may be aerated at times by lifting it with a 

 clean dipper and letting it fall back slowly. A sprinkling can will 

 also serve for this purpose. All vessels and apparatus used in con- 

 nection with the a(|uarium should be perfectly clean, and it is well not 

 to put the hAds into the Avater at all. Assistance in the way of keep- 

 ing the aquanum clean ma}^ be had by introducing a few small tad- 

 poles to act as scavengers, say one to every 15 gallons of water. 



The bottom of the aquarium should be covered to the depth of 

 about 2 inches with fine gravel or clean white sand, in which fishes 

 may rub themselves ; it is also essential for the rooting of plants. 



There should not be too much animal life in the aquarium. The 

 fewer and smaller the fishes the less likely is the air in the water to 

 become exhausted. Two or three small goldfishes to each gallon 

 of water is a safe rule to go by if the aquarium is large. If small, 

 the proportion must be reduced. The question the aquarium pre- 

 sents, when it has been supplied with water and plants, is simply 

 how many fishes or other air-consuming creatures can be accommo- 

 dated in the quantity of water available. Overstocking may disturb 

 the balance within an hour. 



It is probably safe to say that a little neglect in the matter of 

 feeding is better for the permanence of the aquarium than OA^er- 

 attention. It must not be presumed that because fishes will live 

 for months without feeding it is right to treat them in that way. 

 Fishes left without food are simply fishes kept hungry and in a 

 condition of slow starvation, which can only be describee! as cruelty. 

 Wlien there is a large supply of plants in the aquarium the fishes 

 survive longer, the very small ones, especially, getting some nourish- 

 ment from the young shoots of Anacharis and other plants. 



Many aquarists feed CA^ery day, carefully removing all uneaten 

 food, which soon deca^^s and fouls the water. Prepared foods sold 

 by aquaria dealers are generally safe and may be supplied every 

 other day. Finely crushed A^ermicelli is also used. Some of the ordi- 

 nary household cereals are available as goldfish food, but the begin- 

 ner should experiment with them cautiously. Other foods are 

 desirable at times, too. Once a week pieces of very small earth 

 worms or bits of fresh beef should be furnished. If they can be 

 given to each fish on the tip of a broom straw the chances of con- 

 taminating the water by waste food will be lessened. All uneaten 

 food must be picked, dipped, or siphoned out, or foul water and a 

 disturbance of the delicate balance -of the aquarium will result, A 

 milky appearance of the water usually is a warning of careless feed- 

 ing. Nearly all diseases that occur among goldfishes indicate that 

 the aquarium needs looking after. The unsightly growth of fungus 

 on fishes, caused by the plant parasites, Saprolegnia and Devoea, indi- 

 cate careless handling of the fishes or bad conditions prevailing in the 

 aquarium. When the conditions are right diseases are not likely 

 to appear. Too high a temperature favors the growth of fish fungus. 



This disease is hard to deal with, and infected fishes should be 

 removed at once and kept by themselves, where, under proper condi- 

 tions, they may possibly recover. A pinch of salt put in the water 

 with them may arrest the disease, but when in bad condition a tea- 



