BULLETIN OF THE UNITED STATES FISH COMMISSION. 257 



Vol. VI, l¥o. ir. IVashingrton, B. C. ]¥ov. 8, 1886. 



79.-AMKKBCAIV CATFISH IN THE TK0CAI>I<:R0 AQUARIUM OF 



PARIS.* 



By Dr. JOUSSET DE BEELESl^IE. 



These fish,t wliicli measured 12 centimeters [about 4^ inches] in length, 

 were in the beginning-, owing to their small size, placed in one of the 

 tanks for young fish in the aquarium, and remained there till Novem- 

 ber, 1885, when they were put in the large basin No. G. 



They were at first fed with raw meat; but as they did not seem to 

 take very well to this kind of food, they were fed on raw fish chopjied 

 flue, whicb they appeared to like. As soon as they were transferred to 

 the large basin they were fed on live fish. 



The only water at the disposal of the aquarium is that which comes 

 from the Vaune, whose temperature is 15° C. [59° Fahr.] in August 

 and 9° C. [48.2° Fahr.] in December. It is hardly probable that this 

 temperature is sufficiently high for the reproduction of the catfish. At 

 au3' rate, those which we have in our aquarium, no matter to what 

 variety they belong, have never spawned. 



When the American catfish were transferred to basin No. C they 

 were all alive and well, although they had not grown perceptibly. Since 

 that time none of them have died, as far as we have been able to observe, 

 for these fish have a habit of keeping in their holes and never coming 

 out during the day, so that they are hardly ever seen. In basin No. 1 

 we had some of considerable size, and in order to assure ourselves of 

 their existence it became necessary to empty the basin and carefully 

 search for them at the bottom in the cracks between the rocks. Even 

 then we did not always succeed in finding them. I have therefore rea- 

 son to believe that the seven catfish which the Acclimatization Society 

 has given us are still in existence, and the first time the basin is 

 emptied I will search for them again in order to make sure of it. 



I should state that the Trocadero aquarium is by no means adapted 

 to researches of this kind. The impossibility of varying the tempera- 

 ture of the large mass of water which feeds it prevents us from success- 

 fully reproducing any other fish but salmonoids. Moreover, our basins 

 are too large for small fish, which easily escape observation. 



Paris, France, May 28, 1886. 



* " Caiifish dans V aquarium du Trocadero, Paris." From the Bulletin menstiel de la So- 

 ci6l6 Nationah d'accUmaiation de France, Paris, August, 1886. Translated from the 

 French by Hekmax JacOBSON. 



t For note on their receipt see Fish Comraissiou Bulletin for 1886, p. 138; also Fish 

 Commission Bulletin for 1885, p. 433, 



Bull. U. S. F. C, 86 17 



