PARENTAL CARE AMONG FRESH-WATER FISHES. 523 



others, a few of these fishes were exhibited by Mr. Schame, they justly 

 created quite a sensation. In the spring of 1901 the young were 

 ah-eady on the market, and I, as one of the first, obtained four indi- 

 viduals. They were fishes measuring about 5 to (> centimeters in 

 length, which I placed in an aquarium of a capacity of about 45 

 liters of water. The fishes felt apparently quite comfortable in the 

 well-planted basin, ate with relish all that I offered them — earth 

 worms, raw meat, and daphnia — were seldom seen, and thrived per- 

 ceptibly. But after awhile they became more lively in the aquarium, 

 and fights and persecutions took place constantly. It was then seen 

 on closer examination that the four fishes presented a very slight 

 gradation with regard to size. And now the largest was contin- 

 ually pursuing the three others, the second largest did not leave 

 the two smaller in peace, and number three made the smallest the 

 target of his persecutions. The end of the matter was that I with- 

 drew the two smaller, which had already' their fins very much torn, 

 and placed each one by itself, while I left the two larger in the 

 aquarium. Meanwhile July had come, and the larger of the two 

 fishes seemed to take a special pleasure in digging up the whole 

 aquarium, without, however, stopping the j^ersecution of the smaller 

 fish. Everywhere he had dug deep holes into the sand, therein", 

 of course, uprooting many jDlants. When about the middle of July, 

 I examined the smaller fish more closely, it appeared to me as though 

 its body had swollen perceptibly. I did not. however, pay any fur- 

 ther attention to this increase in size, for it did not occur to me that 

 the fishes, only about nine to ten months old, were already about to 

 propagate, but, on the contrary, I took this increase to be a sign of 

 rheir good condition. But from that time on the behavior of the 

 larger fish toward the smaller changed. The persecution stopped, 

 and the larger fish devoted itself exclusively to examining the 

 bottom of the aquarium, Avhich seemed to consist of little hills and 

 valleys. As the sand covering the dirt layer was only about 3 to 4 

 centimeters deep, it happened in some places that the fish also stirred 

 uj) the dirt with it, which could not but intluence the clearness of 

 the water. At last it appeared to have found a place suitable for its 

 purpose; I came to this conclusion l)ecause it l)usied itself for a 

 greater length of time about this place; it had generally taken oidy 

 a short time in making the other holes. 



After some time I saw how the fish dug uj) some vallisnerias in this 

 place, then pulled at them, and finally ])ut the ])lants away with 

 evident exertion. After that it deeiKMied the resulting hole very 

 carefully, fanned away all dirt with its caudal and pectoi-al fins, and 

 went in search of the other previously so l)adly persecuted female. 

 In the meantime the size of the little fish had further increased a 



