Order Cyprinodontiformes
Suborder Cyprinodontoidei
Family Poeciliidae
Subfamily Poeciliinae
Continued…
Green swordtail — Xiphophorus hellerii.
Body shapes and colors of swordtails.
— Bulgarian White – a clearly expressed albinistic form with red eyes. Unlike lemon swordtails, Bulgarian swordtails are hardy and strong in constitution. In origin, they are close to our swordtails. When mating with our marble swordtails (white with black spots), you can get white ones with dark eyes.
— Green swordtail – has a long, narrow, laterally compressed body. The main body color is light olive-brown with a light green sheen, appearing green in reflected light. A red stripe runs from the tip of the snout along the middle of the body and along the caudal fin, and parallel to it run several less distinct reddish stripes. Several rows of reddish-brown spots are located on the yellowish dorsal fin. The sword is nicely bordered at the bottom. The female is colored much paler than the male;
— Red-yellow swordtail – the middle of the body is lemon with a smooth transition to an orange-red color closer to the head and tail. The head itself, as well as the unpaired fins, are brown, as is the stippling on the back from the nape to the base of the caudal fin. In reflected light, the body acquires a golden-sunny sheen. The caudal fin is scarlet, the pectoral, pelvic, and anal fins are light scarlet, and the dorsal fin is yellowish with red dots;
— Red-spotted tiger swordtails – a form that has displaced the old forms of Moscow tigers. The coloration is saturated red with large black spots, the swords are long. But when choosing breeding stock, one should not stop at fish with completely colored black tails and overly black caudal peduncles.
— Red-black swordtail – among their offspring, individual specimens with a black spotted pattern occur, and these are always females. The gene determining the black spotted pattern is linked to the chromosome that determines the female, and therefore can only be inherited by females. If such a female is crossed with a regular red male, females and males with a black spotted pattern can always be found among the offspring;
— Red swordtails – obtained from green swordtails with the participation of red platies. The quality of these fish has noticeably improved in recent years — yellowish-pink and brown shades, white chests, and white ties (Odessa lines of reds) have disappeared. Thanks to repeated crossings with red platies, strict selection, and culling, modern red swordtails have a bright red color and are deservedly called “ruby”;
Photo: Red swordtails — Xiphophorus hellerii.
— Lemon swordtails – an albinistic form of the green swordtail. The same markings as in the green one are present on the colored yellow-green body. The bright lemon form is unstable;
— Multi-striped swordtail – all offspring at the age of 8-11 months have an average of seven stripes on the body. In individual specimens, the number of stripes reaches twelve. Sometimes the right and left sides of the fish’s body have a different number of stripes (by 1-2 stripes). With age, the number of stripes sharply increases to 17 and more. The stripes on the body can appear stronger or weaker. The stripes are clearly visible in gray specimens and almost invisible in colored ones;
— Rainbow swordtails – faintly marked reddish-brown stripes are located along the gray-green body with an orange tint. The fins are bright orange-red;
— Calico swordtails – named so because of their inherent triple coloration — bright red and black spots are scattered across the white background of the body. Breeding work with calico swordtails is quite complex. Properly colored specimens with bright red contrasting spots are very rarely found in broods.
— Tiger swordtails – red fish with black, bred on the basis of hybridizing green swordtails with platies and subsequent crossings with previously bred color varieties of swordtails;
— Tricolor – They cannot be called a breed, broadly speaking, due to the instability of coloration. Fry are usually born white with or without black spots. As they grow, the red color appears, gradually replacing white. If the color replacement process remains incomplete, the fish turns out tricolor. But red-spotted (tiger), rarer red and black-and-white, and very rare white specimens with black ones are also encountered.
— Black-blue swordtail – breeding by crossing a green (natural color) or red female with a black male is not difficult. In the most favorable cases, up to 60 percent of black-blue specimens occur in the offspring. Black-blue coloration can only be obtained by crossing them with the variable platyfish (Xiphophorus variatus) if it has black or black-blue pigmentation. In black-blue swordtails, it is easy to determine what color their mother was — green or red. In the first case, the head and belly of the fish have a greenish-gray tint, in the second — a reddish one. Almost all females of this beautiful form are sterile; the number of black females capable of reproduction does not exceed approximately 1 percent.
— Black swordtail – obtained by crossing a green swordtail with a black platy. Having a long narrow body and a long narrow sword, it is a rare exception. Black swordtails are often less slender than others. The coloration is intensely black with a green or blue tint. Connoisseurs prefer an even matte-velvety coloration. Eyes are light silver with a dark pupil. To enhance coloration and give a velvety look, black swordtails are sometimes crossed with intense red ones.
Photo: Yellow swordtails — Xiphophorus hellerii.
Allotoca diazi, Allotoca dugesii.
Xiphophorus hellerii, Green swordtail. 
