OBSERVATIONS ON THE AQUARIA AT CENTRAL STATION. 
9 
of the development of some absolutely pure and automatic system of filtration for use 
in connection with the establishment of aquaria here and elsewhere. 
It should be stated in explanation of the use of a filter of this character that it is 
the only system yet introduced which will afford a sufficient supply of water and deliver 
it with force so as to provide for the efficient aeration of the water. 
The spawning of the yellow perch ( Perea fla/oescens) in an aquarium in March and 
April of 1888, and again beginning as early as December of the same year and running 
through January, February, March, and up to April 10 of 1889, is further evidence of 
the possibilities of the natural spawning of fish in aquaria. Probably few fish of such 
size would spawn under such restricted conditions, much larger tanks and more natural 
surroundings being required. The smaller species of fish spawn more readily. The 
goldfish and the paradise fish ( Macropodus ) are hatched and reared in the tanks each 
season. 
GENERAL OBSERVATIONS ON THE HABITS OF FISHES IN THE AQUARIA. 
SPAWNING HABITS OF THE DARTERS. 
During April and May of 1889 a number of spawnings of the “tessellated” darter 
[Boleosoma olmstedi) were observed. The eggs were deposited on the under surfaces 
of stones, or on the backs of them, where one leaned against the ends or back of the 
tank, or against another stone, in a single irregular layer over an area of about 1 by 3 
inches. They were about the size 
and appearance of those of the com- 
mon sunfish and were deposited in 
the same manner. The great activ- 
ity and brilliant coloration of the 
male, which is ordinarily one of the 
most sober-hued of the darter family, 
differing but little from the female, 
were very conspicuous. 
The spawning was effected by 
passing up and down over the sur- 
face chosen until all the eggs were 
extruded and adhering to the stone. 
The fish undoubtedly pair, for, al- 
though all the males would be in a 
state of great excitement and would 
endeavor to join in the operation, 
they were invariably driven away by 
the successful male, who would dart 
at them furiously with open mouth 
and fins quivering with excitement, 
the colors glowing with increased 
brilliancy and intensity. The male 
guards the eggs incessantly and 
drives every fish from their vicinity during incubation, retaining the brilliant color 
until that duty is over. 
Fig. 1. Eggs of the Tessellated Darter (Boleosoma olmstedi) 
spawned in Aquaria. 
