Swordtail fry is the newborn offspring of swordtail fish. Swordtail fry require specific care in order to ensure that the fry survives until they reaches adulthood. Swordtail fish are livebearers; they gives birth to live young offspring rather than laying eggs.
A female swordtail fish will deliver between 20 and 80 fry after a gestation period of 28 to 30 days. Signs of pregnancy in a female swordtail include a body that appears “boxy” when viewed from the side and a dark spot on the fishs belly. When swordtail fry are born, they are free swimming and measure 0.3 inches in length.
Caring for Swordtail Fry
Additionally, the fry have used up the yolk sacs that were attach to the fry at the time of birth. One of the primary requirements of caring for swordtail fry is to provide protection for the fry; adult swordtail fish will eat the newborn fry. Isolating the fry in a breeder box or tank will prevent the adult swordtail fish from eat the fry.
Floating breeder boxes that contain mesh allow the fry to leave the breeder box while the adult swordtail fish remains within the tank. This method of breeding can improve the survival rates of fry. The fry must be fed an appropriate diet as they grows.
Newborn swordtail fry have mouths that are too small to eat flakes, so you should feed infusoria to fry newborn to four week old fry. You can culture infusoria by placing a lettuce leaf into the tanks old water and allowing the infusoria to grow. At one week old, the fry should be fed microworms.
Two week old fry can be fed baby brine shrimp, which contain the protein required for fry growth. The fry will double in size every few weeks, so feeding is essential for survival. At three to four weeks old, you can feed crushed flakes to fry.
At six weeks of age, mini pellets can be introduced to the diet of fry; at this age, male swordtail fry begin to develop their swords. Newborn swordtail fry are nearly transparent in appearance. The fry have soft fins and no visible color.
By the fourth week of life, the frys body shape solidifies and their colors appear. Male swordtail fry begin to develop their swords; the elongated fins along the bottom of the fish. Male swordtail fry develop these swords by the eighth week of age.
Female swordtail fry do not develop a sword, but do develop fan-shaped fins along their rear end (anal fins) and a dark spot on their belly (gravid spot). Being able to determine the sex of the fry allows for the separation of male from female swordtail fry. The fry should be kept in a 5 to 10 gallon grow-out tank that is populated with sponge filter.
The firmness of a sponge filter ensures that the fry are not exposed to strong water currents that may pull the fry into the filter of the tanks filtration system. Providing plants, such as java moss or hornwort, allows fry to hide from sight from other fish in the tank. Additionally, plants will help to oxygenate the water.
At the time of their birth, the fry should be kept at a density of three fry per gallon of water in the tank. As the fry mature, the density should be reduced to one swordtail fry per gallon of water. Daily water changes of 20 percent should be performed to remove waste from the tank.
Excessive ammonia in the tank can lead to bloat or swim bladder issues for the fry; swim bladder issues cause the fry to lie on their side in the tank. Swordtail fish come in a variety of different varieties. However, regardless of the variety of swordtail fish that is observed, the growth patterns of the fry are the same.
Red swordtail fish are scarlet in color; green swordtail fish are olive in color and black swordtail fish are melanistic in color. Pineapple morph swordtail fish are yellow-orange in color and kohaku swordtail fish have markings on their body that is similar to those of koi fish. The colors of swordtail fry become vibrant around the twelfth week of age.
Swordtail fish require specific water parameters to thrive. The water temperature should be maintained between 72 and 79 degrees Farenheit. The pH should be between 7.0 and 8.4.
Swordtail fish thrive in hard water; adding salt to the tank can increase the growth and vigor of fry. Common errors in feeding swordtail fry include feeding too many flakes to the fry and underfeeding the fry. Feeding too many flakes to the fry will lead to the flakes adhering to the tanks bottom; underfeeding the fry will result in stalling in the growth of the fry, causing some fry to be “runts” in size relative to other fry of the same age.
It is best to avoid adding other fish species to the tank until the swordtail fry reach 12 weeks of age. Should a fry develop a swim bladder issue due to constipation, a fasting day for the fry will allow the swim bladder to return to normal; afterwards, feeding the fry a small piece of blanched pea will restore the normal elimination of the frys waste. Once mature at around 12 weeks of age, swordtail fish can be kept in community tanks with other peaceful fish species.
Peaceful fish species that can be kept with swordtail fish include mollies, platies, tetras and other species that do not nip the swords of the male swordtail fish. Corydoras, danios and otocinclus fish are three other species to consider for keeping in the same tank as swordtail fish.
