HABITS OF SOME OF THE COMMERCIAL CAT FISHES. 
407 
a tendency to bank np or school together like young salmon. They also, like young salmon, tended 
to face or swim against the current in the aquarium, a habit common, in fact, to most young fishes 
recently hatched. * * * 
On the fifteenth day after oviposture it was found that they would feed. While debating what 
we should provide for them, Mr. J. E. Brown threw some pieces of fresh liver into the aquarium, 
which they devoured with avidity. It was now evident that they were provided with teeth, as they 
would pull and tug at the fragments of liver with the most dogged perseverance and apparent ferocity. 
This experiment showed that the right kind of food had been supplied, and, as they have up to this 
time (August) been fed upon nothing else, without our losing a single one, nothing more seems to be 
required with which to feed them. 
It is worthy of note that when pieces of liver were thrown into the aquarium the parent fishes 
would apparently often swallow them, with numbers of young ones eating at and hanging to the 
fragments. I was soon agreeably surprised to find that the parent fishes seemed to swallow only the 
meat, and that they invariably ejected the young fish from the mouth quite uninjured, the parent fish 
seeming to be able to discriminate instinctively, before deglutition occurred, between what were its 
proper food and what were its own young. As soon as the young began to feed they commenced to 
disperse through the water and all parts of the aquarium, and to manifest less desire to congregate in 
schools near the male, who also abated his habit of fanning the young with his fins, as was his wont 
during the early phases of development. 
Regarding the breeding habits of Ameiurus nebulosus, Dean (loc. cit.) says: 
In breeding habits the cat-fish still maintains its reputation for hardiness. It spawns rapidly, 
even when transferred to aquaria. The eggs are one-eighth inch in diameter and are adhesive, 
reminding one somewhat of frog spawn. The mass is deposited in shallows where the bottom is 
sufficiently hard to support its weight. The danger to the egg occasioned by stagnancy or muddiness 
of the water is carefully provided for; the male, standing guard, forces the water slowly through them. 
In some of the southern species, for thorough aeration, the male turns to account the operation of 
breathing, filling the back of the mouth often so full of eggs that the whole face and throat are 
distended. In the neighborhood of New York the spawning season is in the early part of April, and 
appears to last about a fortnight. Toward the latter part of the month the females go into deeper 
water. At this season (Central Park) of a dozen fish caught, ten proved to be males. 
A similarity of breeding habits in Ameiurus nebvlosus and Ameiurus catus is 
shown by comparing the observations a presented in a paper by Dr. H. M. Smith to 
the American Association for the Advancement of Science and a notice * * 6 of which 
appears in Science (February 13, 1903, 243) with the preceding record of Dr. Ryder. 
Dr. Smith observed: 
A pair of fish from the Potomac River in the Fish Commission aquarium at Washington made 
a nest on July 3, c 1902, by removing in their mouths upwards of a gallon of gravel from one end 
of the tank, leaving the slate bottom bare. On July 5 about 2,000 eggs, in four separate agglutinated 
clusters, were deposited between 10 and 11 a.m. on the scrupulously clean bottom. Ninety -nine per 
cent hatched in fire days in a mean water temperature of 77° F. The young remained on the bottom 
in dense masses until 6 days old, when they began to swim, at first rising vertically a few inches and 
immediately falling back. By the end of the seventh day they were swimming actively, and most of 
them collected in a school just beneath the surface, where they remained for two days, afterwards scat- 
tering. They first ate finely ground liver on the sixth, and fed ravenously after the eighth day. The 
fish were 4 mm. long when hatched, and grew rapidly, some being 18 mm. long on the eleventh day, and 
at the end of two months their average length was 50 mm. Both parents were very zealous in caring 
for the eggs, keeping them agitated, constantly by a. gentle fanning motion of the lower fins. The most striking 
«See also Observations on the Breeding Habits of Ameiurus nebulosus. Doctor A. C. Eycleshymer. (The American 
Naturalist, November, 1901, 911.) 
6 For the complete account see Breeding Habits of the Yellow Cat-fish. Hugh M. Smith and L. G. Harron. (U. S. F. C 
Bull., 1902, 151-154.) 
c Italics by the writer to show close similarity to Ryder’s observations. 
