This section is from the book "The Goldfish And Its Systematic Culture With A View To Profit", by Hugo Mulertt. Also available from Amazon: The goldfish and its systematic culture.
( Carassius japonicus) Japanische Goldfische. Poisson d'Orient.
In introducing this variety of fish to the attention of the reader, it may be said that the description of the mode of reproduction, habits, etc., regarding the common goldfish, equally apply to the Japanese and Chinese varieties, as they are members of the same family, differing only in shape and color.
The Japanese specify the goldfish by the shape of the body and that of the fins, the coloring in most species being the same. The prevailing colors are vermillion, gold and white, if indeed the last can be called a color.
The Japanese classification being rather complicated, the species' names will be omitted for convenience sake, and the fish described in the manner others have been, though at the same time retaining the foreign nomenclature.
This fish is indeed an odd looking affair. The body is spherical very much like that of a frog-tadpole, and covered, as all goldfishes are, with medium-sized scales. The fins, are very delicate in structure; the anal fin mostly absent; the caudal fin is double, very large and deeply divided. The eyes are large and project forward, having the appearance of a small telescope adjusted to the eye (see illustration), from this the fish received the name it bears. To make the eyes more prominent the Japanese culturist resorts to an ingenious device. He places the young fish in small dark-glass vessels shaped for the purpose, and which obliges the fish to look constantly in but one direction.
The color of the fish may be either vermillion, white or part of both, the markings in that case being very beautiful. The body of the fish is all out of proportion to the size of the fins, and in consequence propulsion is a difficult matter.
In spawning, the male rolls the female about among the stones in a most pitiful manner, sometimes for days together; this is an effort of the male to assist in the extrusion of the eggs. When spawned the eggs attach themselves to the stones and other substantial objects rather than to water-plants, probably because it is amongst the stones that the extrusion takes place.
When the young are first hatched, they appear exactly like the common goldfish. They rest upon the water-plants or other supports for a couple of days, at the end of which time the yolk-bag is absorbed; then commences the struggle for existence. The double tail, which is even then large enough to be distinguished, hinders the tiny creatures (but one-quarter of an inch in length) in their movements in the water. Should they find sufficient food to make a bountiful meal, matters become still worse, they lose their balance and can not go at all until digestion is completed, in the meanwhile falling an easy and welcome prey to numerous enemies.
For this reason, which is the main one, and because the fish is very difficult to propagate, it is exceedingly rare, even in Japan.
When mature, the telescope fish is about the size of a man's fist.
The body of the fringe-tail is short, egg-shaped and slightly compressed; the eyes normal, but very variable in the color of the iris, which is that curtain in the anterior portion of the eye that by its contraction and dilation, regulates the quantity of light that enters the optic. In this fish the color of the iris may be any color, excepting green only, in different individuals.
The fins are large and of very fine structure; the anal fin is double, while the caudal may be either double, treble or quadruple, as the case may be, and is larger than the body, drooping very gracefully. (See illustration.) These special characteristics, among all the fancy varieties, are not fully developed until the second year. In the coloring of the body and fins this fish is not surpassed by any other, making one of the most valuable and desirable objects for the aquarium. There are specimens the back and sides of which are deep vermillion, the abdomen, throat and eyes of rich gold, while all the fins are milk white. Others again will be found presenting a rich vermillion on that part of the body forward of the dorsal fin including the throat, part of the abdomen, and the respective fins, while all back of that is pure white. Some there are with body all white, the fins red, and vice versa; others pearly, dotted with irregularly shaped pink spots, the eyes being blue; again, the entire fish will be white, the only touch of color being the deep red of the large eyes. In fact, it is impossible within the limits of this sketch to enumerate the endless variety of the markings to be seen, and one can only get an adequate idea by examining a large number.
Strange as it may seem, this beautiful species of fish was nearly lost to this country through the caprice of private individuals who happened, or rather were lucky enough, to possess perfect specimens, and were unwilling that others should enjoy the possession of the like. But fortunately, a lady both generous and appreciative, rather than that the stock should die out, loaned to the author for the purpose of reproduction several fine specimens she had recently obtained. The pure stock may now be considered secure for the future. In evidence of the extreme beauty of the species, it may be stated that private parties paid for fine specimens twenty times the weight of the fish in gold.
What has been said about the difficulty of raising telescope fish, may with almost equal propriety be repeated for the fringe-tail. Unlike the former, the latter fish spawns against aquatic plants, the extrusion of the eggs not being so difficult.
The body is elongated and compressed on the sides; the head pointed; the fins are short and stout, the anal sometimes double, and occasionally found wanting. The caudal fin is comparatively short, is double, with the upper edges grown together; it is sometimes erect like that of the fantail pigeon (see frontispiece), or projects horizontally. The colors are mostly vermillion and white; in some cases the whole body is white, with the exception of the abdomen, this being golden; in others the body is dark red, the belly also golden. The color of the eyes is variable.
THE JAPANESE FANTAIL GOLDFISH. (Carassius Japonicus)
It may be mentioned here as an advantage of the double-tailed fish, that they are unable to jump out of the water. This fact is undoubtedly one to be appreciated by those keeping an aquarium.
This is a noble looking fish, and greatly resembles the fantail.
Its body is slender, the fins very large and of fine structure; the caudal fin is single and deeply divided. The coloring is identical with the preceding.
The body of this species is oblong, and much compressed on the sides; the head is short, and fins normal. The color varies from a light to a deep vermillion, sometimes white; a background of white beautifully dotted with crimson, the throat golden, makes a magnificent combination that is very ornamental indeed.
The sub-varieties of this are the Ramsnose and the Hognose.
That part of the body of this fish from the mouth to the dorsal fin forms a bow, like the forehead of a ram, this feature giving the fish its name. The lower part of the body from the mouth to the tail continues a straight line.
The peculiarity of this fish is just the reverse, concaved, greatly resembling the head ot a fat hog.
All of the goldfish described above do not attain a very great size, seldom attaining a length of more than eight inches.