quantity of water can be determined as it 

 depends on the varying conditions recorded 

 above, and also the size and character of the 

 fish, some of them requiring more oxygen than 

 others, and large fish more than small ones. 



It is a question that can only be settled by 

 actual experiment in each individual case. Any 

 attempt to establish a rule of so many fish to 

 the gallon of water is the result of ignorance. 



Many of the details of aquarium management 

 are matters of individual preference and may be 

 carried out in different ways with equally satis- 

 factory results, but the fundimental require- 

 ment of ample sunlight cannot be disregarded 

 without complete or partial failure. 



With small aquaria some modifications of the 

 sunlight may be found necessary during the 

 hottest part of the day, but this is so easily ar- 

 ranged in various ways as to need no elucidation. 

 If they are stocked with fishes of proper size and 

 in due proportion there is no more difficulty than 

 with large aquaria. I make use of jars of any 

 size from a quart up, and a one gallon jar makes 

 a good sized breeding aquarium for the small 

 viviparous fishes, sufficing for a number of pairs. 



It is not high temperature that causes dis- 

 tress to fishes, but lack of oxygen resulting from 

 it. I have kept large trout of various species at 

 temperatures ranging from 70 to 80 degrees F. 

 without evidences of discomfort, but this, of 

 course, in artificially aerated water. It is proba- 

 ble that they could be adapted by degrees to live 

 in an ordinary aquarium, and this I suggested 

 many years ago. 



In a letter written to me in 1912 by Mr. Fred 

 Metcalf, he tells of an experiment he made in 

 keeping two trout fry in a nature aquarium, 

 viz: "These two fry, which had been hatched in 

 the wild state were placed by themselves in a 

 fifty gallon aquarium of perfectly stagnant water 

 with no mode of aeration whatever except that 

 due to a luxuriance of thriving plant growths. 

 Living food was profusely abundant in the form 

 of multitudes of protozoans and minute crus- 

 taceans, upon which they fed constantly. I was 

 able to keep them for several weeks, during 



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