American Flagtail

 

fish description – Flagtail Prochilodus Care Guide ($Semaprochilodus\ taeniurus$)

Category	Detail
Scientific Name	$Semaprochilodus\ taeniurus$ (or $S.\ insignis$)
Common Name	Flagtail Prochilodus, Flagtail Characin, American Flagtail
Origin	Amazon and Orinoco River Basins (South America)
Adult Size	10–14 inches (25–35 cm)
Temperament	Generally peaceful, but boisterous; semi-aggressive toward conspecifics
Lifespan	5–10 years
Care Level	Advanced (due to eventual size and specialized diet)

Export to Sheets

---

 

Appearance and Sexual Differences

 

• Short Description: A robust, deep-bodied fish with a silvery-white body and a small, fleshy mouth adapted for scraping algae and detritus. The most distinguishing feature is the flag-like tail marked with bold, alternating red and black horizontal stripes.
• Coloration: Silvery-white or gold body with orange-red fins. Juveniles of some species may have dark spots on their flanks that fade with age. Sexing is difficult; females are generally slightly plumper or more rounded than males.
• Fins: The caudal fin (tail) features the striking red and black stripe pattern.
• Behavior: Extremely active, energetic shoaling fish that constantly cruises the middle water column. They are migratory in the wild, underlining their need for vast open swimming space. They are notorious jumpers and require a very secure, heavy lid.

---

 

Tank Requirements and Water Parameters

 

• Minimum Tank Size: 125 gallons (475 liters) or larger is the minimum for a single adult. Due to their length and constant movement, a tank length of 6 feet or more is necessary for a small group.
• Schooling: Best kept singly (as a centerpiece) or in a large group of 6 or more individuals to spread out mild conspecific aggression.
• Temperature: Tropical range: $75^\circ$–$82^\circ\text{F}\ (24^\circ$–$28^\circ\mathrm{C})$.
• pH Level: Soft, neutral to slightly acidic water: 6.0 to 7.5. They require pristine, highly oxygenated water with a moderate current.
• Aquascape: Requires vast open horizontal swimming space in the center. Decorate with a sandy substrate, smooth rocks, and vertical driftwood pieces, but keep these elements arranged along the sides. Avoid soft-leaved plants, as they are herbivores and will graze on them.

---

 

Diet and Feeding

 

The Flagtail Prochilodus is primarily a herbivore/detritivore that needs high plant matter content.

• Staple Diet: The diet must be high in vegetable matter. Offer high-quality algae wafers, spirulina pellets, and sinking foods intended for herbivores.
• Supplementation: Feed plenty of blanched fresh vegetables (zucchini, cucumber, peas, spinach/lettuce). They will accept frozen/live meaty foods (bloodworms, brine shrimp) but this should only be a small part of their diet.
• Schedule: Feed small amounts multiple times a day to satisfy their grazing instinct and prevent them from eating plants.

---

 

Compatibility

 

• Caution: Will eat soft-leaved plants. They are boisterous at feeding time and can be competitive. Avoid small fish (like Neon Tetras) as they may occasionally be consumed. They are aggressive toward their own kind if kept in groups smaller than six.
• Good Tank Mates: Other large, robust, and peaceful to semi-aggressive fish. Excellent dither fish for large cichlid tanks. Examples include Silver Dollars, Severums, Angelfish (large adults only), L-number Plecos, and large Catfish.