Description
Yellow Tailed Flagtail Barb
Scientific Name: Semaprochilodus insignis
Common Names: Yellow Tailed Flagtail, Flagtail Prochilodus, Yellow Tail Prochilodus
Overview
The Yellow Tailed Flagtail Barb is a striking freshwater fish distinguished by its shiny silver body and boldly striped yellow and black tail fin. A color variation of Semaprochilodus insignis, this impressive species is native to the Amazon and Orinoco river basins. Peaceful but energetic, it thrives in large, well-oxygenated aquariums with plenty of swimming room. Like its red-tailed relatives, it is a hardy grazer and an excellent addition to big, river-themed tanks.
Key Information
Size: Up to 12 inches (30 cm)
Lifespan: 8–10 years or more
Temperament: Peaceful, active swimmer
Diet: Primarily herbivore and detritivore
Swimming Level: Mid to bottom
Habitat & Tank Setup
Tank Size: Minimum 125 gallons (larger recommended for adults)
Group Size: Can be kept singly but prefer small groups (3–6)
Substrate: Sand or smooth gravel
Decor: Large driftwood, smooth stones, plenty of open space
Plants: Tough or floating plants (may nibble delicate plants)
Lighting: Moderate to bright
Filtration: Strong filtration and high oxygenation; moderate water current preferred
Water Parameters
Temperature: 75–82°F (24–28°C)
pH: 6.0–7.5
Hardness: Soft to moderately hard (3–12 dGH)
Water Quality: Excellent water quality critical due to size and active behavior
Feeding
Diet Type: Primarily herbivore
Suitable Foods:
Algae wafers, spirulina flakes
Blanched vegetables (spinach, peas, zucchini)
Occasional frozen foods (bloodworms) for variety
Feeding Frequency: 1–2 times daily; offer small meals to prevent water fouling
Tankmates
Compatible With:
Large peaceful fish (silver dollars, peaceful cichlids, bala sharks)
Other Flagtails or large characins
Avoid:
Very small fish that could be stressed by their activity
Aggressive fish that may harass them
Care Notes
Excellent jumpers — secure, tight-fitting tank lid is required
Will constantly graze surfaces for algae and biofilm
Needs plenty of swimming space and moderate water movement
Social behavior is more natural when kept in groups
Juveniles are more tolerant of tankmates; adults need more space
Fun Fact
Yellow Tailed Flagtail Barbs are important in their natural ecosystem for algae control and nutrient cycling, playing a key role in the health of the Amazon’s vast floodplain waters!
