Redfin Flagtail Prochilodus (Semaprochilodus taeniurus)

The Redfin Flagtail Prochilodus is one of the most active and visually striking schooling fish in the freshwater hobby. Known for its shimmering silver body and bold red fins, this species brings constant movement and energy to large aquariums.

Unlike typical “monster fish,” flagtails are peaceful, algae-grazing swimmers that thrive in groups and are perfect for balancing out aggressive tank mates.

Max Size

• Up to 18–24 inches in captivity
• Fast growers when properly fed and housed

Tank Size

• Minimum: 180 gallons
• Recommended: 300+ gallons for a small group
• Best kept in groups of 3 or more to reduce stress and encourage natural schooling behavior

Tank Mates

• Large, non-aggressive to semi-aggressive fish
• Great with:
  • Arowana
  • Datnoids
  • Large catfish
  • Stingrays
• Avoid small fish (may be outcompeted or stressed)

Diet

Primarily herbivorous with omnivorous tendencies:

• High-quality sinking pellets
• Algae wafers
• Fresh vegetables (zucchini, spinach, peas)
• Occasional protein (shrimp, bloodworms)

👉 Known for constantly grazing on algae and biofilm—great for helping keep tanks clean

Care & Behavior

• Extremely active swimmers—need long tanks with open space
• Prefer strong filtration and high oxygen levels
• Peaceful but very energetic—can outcompete slower fish for food
• Thrive in well-maintained, stable water conditions

Why We Love Them

• Eye-catching red fins with a metallic body
• Constant movement—brings life to any large tank
• Excellent “clean-up crew” for monster fish setups
• Hardy and adaptable once established