92 THE GOLDFISH AND ITS CULTURE. 
The coloring attained by the fish generally remains so, though 
there are instances in which the red markings may become milky 
white, and what was previously white changes to red, or black spots 
may appear, or if present, be lost. This may occur either wholly or 
in part. A satisfactory reason for this phenomenon can not be 
given. 
The selection of faultless beauties for breeding purposes, how- 
ever, is not absolutely necessary, such specimens are best kept for 
exposition purposes. Any fish whose fins may have become injured 
in any way, by accident or otherwise, but have grown again in some 
crooked or objectionable shape, are nevertheless perfectly fit for the 
spawning bed, if they are otherwise in perfect condition, though for 
ornamental purpose they would be of little account. 
It may be remarked in this connection, and with propriety, that 
certain peculiarities in the shape of foreign fish, ¢ ¢., those newly 
introduced, are in the course of time, lost, when imported into the 
* United States, the change of climate, locality, food, etc., producing 
gradual changes in their typical forms, assuming or acquiring, so to 
speak, an American type. In view of this, the culturist should 
never neglect to infuse new blood into his stock whenever a favor- 
able opportunity offers, for by so doing he can keep it up as near to 
the original standard as it is possible to do under the change of 
circumstances. 
At the breeding season the sexual differences are plainly revealed 
to the practiced eye of the patient observer—not before. Upon 
close inspection the bony plates that cover the gills, the gill-covers, 
or opercles, wili be found covered with small white prominences, 
usually denominated tubercles. Those fish bearing this distinguishing 
mark are male fish. These tubercles appear on the fish when it 
is in condition for reproduction, and disappear when that 
function ceases to be in an active state. This period may be of longer 
