Xenotoca doadrioi - Redtail Goodeid. CARES.... Critically Endangered

Xenotoca doadrioi (San Marcos Redtail Splitfin / Redtail Goodeid)

​Add a stunning splash of vibrant color and a vital piece of conservation history to your fish room with the true Xenotoca doadrioi. Formerly lumped in with Xenotoca eiseni, this distinct species hails from the Etzatlan region near San Marcos in Jalisco, Mexico. Highly sought after by livebearer enthusiasts and conservationists alike, this active and hardy fish makes an incredible centerpiece for a dedicated species setup while actively contributing to global preservation efforts.

​Key Features & Appearance
​Stunning Dimorphism: Fully mature males showcase a brilliant orange-to-red caudal peduncle bordered by an iridescent blue band, complemented by a golden-yellow body saddle, metallic blue scales, and a golden-yellow chin and belly.

​Compact Size: A wonderfully manageable nano-to-medium livebearer. Females reach up to 2 inches, while males stay slightly smaller at around 1.5 to 1.75 inches, making them ideal for standard-sized aquariums like a 20-gallon long.

​Livebearing Fascination: As members of the Goodeidae family, they do not lay eggs; instead, they give birth to remarkably large, well-developed free-swimming fry after a roughly 60-day gestation period.

​Conservation Status & CARES Program
​Critically Endangered: Xenotoca doadrioi faces severe threats in its native wild habitats due to severe water extraction, habitat degradation, and invasive species introduction in the Etzatlán region.

​CARES Preservation Program: This species is a high-priority participant in the CARES Preservation Program, an international initiative dedicated to maintaining pure strains of endangered freshwater fish in private home aquariums. Keeping and responsibly distributing Xenotoca doadrioi helps ensure these magnificent fish survive outside of nature as a living ark against extinction.

​Care & Aquarium Requirements
​Tank Setup: Thrives in a well-maintained aquarium with plenty of visual barriers, driftwood, and robust live plants to break up lines of sight. A species-only setup is strongly recommended to protect this critically endangered regional variant and manage their active, occasionally assertive colony dynamics.

​Temperature: Unlike many tropical fish, they prefer cooler, temperate water. They thrive at room temperature between 60°F and 75°F and typically do not require an aquarium heater unless room temperatures drop excessively.

​Water Parameters: Highly adaptable, but performs best in moderately hard, alkaline water with good oxygenation and low nitrates maintained via regular partial water changes.

​Diet: Omnivorous and unpicky. They readily accept high-quality flakes, micro-pellets, and small frozen foods. Because vegetable matter heavily comprises their natural diet, incorporating spirulina-based foods and green matter is essential for long-term health.