THE AQUARIUM, OCTOBER, 1895. 



surface appeared to assume where they 

 were, a red tinge. 



The Hudson River is famous for its 

 eels, and small specimens of these were 

 occasionally brought to me. A scoop- 

 net, drawn through the liquid mud in 

 any of the tide- water pools along the 

 river margin generally brought up 

 more or less small eels, so that a good 

 selection could be made of the size best 

 adapted for observation. From the ex- 

 perience I gained with them, I would 

 never recommend more than one small 

 eel being placed in an aquarium, as two 

 which I first introduced took up their 

 respective quarters at either end of the 

 tank, and were perpetually doing battle 

 like knights of old, charging on each 

 other most furiously, with the final re- 

 sult one morning of my finding both 

 dead on the surface of the water, one 

 of them having half swallowed the 

 other, but the latter in the operation 

 choked his conquerer, with the result 

 mentioned. A subsequent specimen of 

 mine was in the habit of secreting him- 

 self between two stones, with part of 

 his body only exposed, as if watching 

 everything. There is apparently much 

 of the snake in their habits, and the 

 same timidity exists in each. The 

 least noise disturbs their equanimity, 

 and thunder seemed particularly to af- 

 fect my specimen. Although he oc- 

 casionally moved round in the daytime, 

 night was the time for his activity, and 

 the artificial light of a room seemed in 

 no way to interfere with his apparent 

 recognition of time. One eel at a time 

 affords ample opportunities for study- 

 ing the habits of that family. 



One of the most interesting fish to 

 watch is the cat-fish, Avhich I am sel- 

 dom without, but it must be kept well 

 fed, and even then the fins and tails of 

 other fish bear evidence of its attacks 



upon them. It is astonishing what an 

 amount of food a cat-fish will swallow. 

 You can watch its stomach swelling out 

 to such an extent that it presents the 

 appearance of a fowl's crop when fed to 

 repletion. After he has thoroughly 

 bloated himself out, he generally settles 

 down, under or beside a stone, and lies 

 there in a sort of comatose state for 

 some time, closely resembling in this 

 the serpent family. As soon as the 

 effects of his meal has passed off, he 

 becomes one of the most restless of the 

 occupants of the aquarium, and swims 

 backward and forward and up and 

 down, incessantly, as if calling atten- 

 tion to his wants. I have not the 

 slightest doubt that, after a time, fish 

 know intuitively, to a certain extent, 

 when feeding time comes and the party 

 that feeds them. I think the cat-fish 

 are affected by, and feel coming changes 

 of weather, but one cannot deduce con- 

 clusions from observations taken in a 

 room where the temperature is probably 

 uniform, as compared with the natural 

 temperature out of doors. 



Sticklebacks I have had in abundance, 

 but more than two at a time become a 

 nuisance. It is a perpetual warfare all 

 round, especially if the males predom- 

 inate. They, together with sun- fish, 

 are probably the most pugnacious of 

 all fish showing hostility even to my 

 finger when held towards them under 

 water, their fins and spines bristling up 

 like the hairs on a bull-dog's neck, 

 when excited. They snap at every- 

 thing, and it is impossible to keep any 

 larva? in an aquarium any length of 

 time if these fish are joint occupants. 

 I have read of sticklebacks building 

 their nests and breeding among the 

 weeds in an aquarium, but I never wit- 

 nessed any operation of this kind my- 

 self, as I frequently changed my tenants- 



