Flagtail Prochilodus

The Flagtail Prochilodus is one of the Amazon Basin's most charismatic and visually distinctive fish — a silvery, deep-bodied species instantly recognizable by its spectacular caudal fin, which displays bold horizontal stripes of black and vivid red-orange that flare like a semaphore flag when the fish swims. Semaprochilodus taeniurus is a detritivore and herbivore that plays a critical ecological role in Amazonian river systems, consuming algae, biofilm, and decomposing organic matter in vast migratory schools that can number in the millions. In the aquarium, this same feeding behavior makes the Flagtail Prochilodus one of the most effective natural algae control species available for large tanks.

At The Fish Collection, we source our Flagtail Prochilodus from established South American exporters who collect sustainably from abundant wild populations. Each specimen is quarantined and acclimated to prepared foods before listing. These fish reach approximately 12 inches in captivity, with a laterally compressed body that gives them a substantial, impressive presence despite their moderate length.

Housing requires a minimum 200-gallon aquarium for a small group. Flagtail Prochilodus are active, fast-swimming fish that need ample open space for schooling. They are best kept in groups of four or more, as solitary specimens become shy and fail to display their natural behaviors. A secure, heavy lid is mandatory — this species is an enthusiastic jumper that will launch itself out of uncovered tanks with alarming frequency. Substrate can be sand or gravel, and decorations should include large rocks and driftwood that provide algae-growing surfaces.

Water parameters should mirror Amazonian conditions: temperature between 72 and 82 degrees Fahrenheit, pH of 6.0 to 7.0, and soft to moderately soft water. Strong filtration with moderate flow replicates the river environments this species inhabits. Weekly water changes of 25 percent maintain optimal conditions.

Diet is herbivorous. Offer spirulina pellets, algae wafers, blanched vegetables, nori sheets, and fresh vegetable matter. The Flagtail Prochilodus constantly grazes on tank surfaces, consuming biofilm and algae with a specialized sucker-like mouth that is perfectly adapted for scraping. This grazing behavior keeps tank surfaces remarkably clean. Temperament is peaceful — one of the few large Amazonian species that genuinely works in a community setting without posing a threat to smaller tankmates. They school beautifully and add both movement and practical algae control to large displays.