Description
Red Tailed Shark (Epalzeorhynchos bicolor)
Overview
The Red Tail Shark, Epalzeorhynchos bicolor, is a striking freshwater fish native to Thailand’s rivers and streams, particularly the Chao Phraya and Mekong basins. Known for its sleek black body and vibrant red tail, it is a popular but semi-aggressive addition to aquariums. Often mistaken for the Rainbow Shark (Epalzeorhynchos frenatum), it is slightly more territorial and better suited for aquarists with experience managing aggressive behaviors.
- Scientific Name: Epalzeorhynchos bicolor
- Size: 4–6 inches (10–15 cm)
- Lifespan: 5–8 years with optimal care
- Temperament: Semi-aggressive, highly territorial
- Tank Level: Bottom to mid-water column
Care Requirements
Red Tail Sharks are hardy but require specific conditions to thrive:
Tank Size: Minimum 55 gallons (208 liters) for a single Red Tail Shark. Larger tanks (75+ gallons) are recommended for community setups to minimize territorial conflicts.
Water Parameters:
- Temperature: 74–80°F (23–27°C)
- pH: 6.5–7.5 (slightly acidic to neutral)
- Hardness: 5–15 dGH (soft to moderately hard water)
- Ammonia/Nitrite: 0 ppm
- Nitrate: <20 ppm
- Substrate: Smooth gravel or sand to prevent injury to their underbellies. Dark substrates enhance their red tail coloration.
- Filtration: Strong filtration with moderate flow (e.g., canister filter) to maintain pristine water, as they are sensitive to poor water quality.
- Lighting: Moderate; they tolerate varied lighting but prefer setups with shaded areas or caves to reduce stress.
- Decor: Provide caves, driftwood, and robust plants (e.g., Anubias, Java fern) to establish territories and hiding spots. Ensure open swimming spaces for their active nature.
Maintenance
- Water Changes: Perform 25–30% water changes weekly using dechlorinated water matched to tank parameters to maintain water quality.
- Tank Cleaning: Lightly vacuum substrate during water changes to remove debris, avoiding disruption of hiding spots or decor.
- Equipment Checks: Regularly inspect filters, heaters, and thermometers to ensure stable conditions, as Red Tail Sharks are sensitive to fluctuations.
- Territory Management: Rearrange decor periodically to disrupt established territories if aggression becomes an issue.
Diet
Red Tail Sharks are omnivorous with a varied diet:
Staple Diet: High-quality sinking pellets or flakes (e.g., Hikari Sinking Pellets, Omega One Freshwater Flakes).
Supplementary Foods:
- Live or frozen foods: Bloodworms, brine shrimp, daphnia.
- Blanched vegetables: Zucchini, cucumber, spinach (secured to sink to the bottom).
- Algae wafers: They graze on algae naturally, so algae-based foods are beneficial.
Feeding Frequency: Feed small amounts 1–2 times daily, ensuring food reaches the bottom or mid-water column. Remove uneaten food after a few hours to prevent water fouling.
Note: They are aggressive feeders and may outcompete slower tankmates, so ensure all fish have access to food.
Behavior and Compatibility
Behavior: Red Tail Sharks are highly territorial and semi-aggressive, often claiming caves or specific tank areas. They are active swimmers, primarily at the bottom and mid-levels, and may chase other fish to defend their territory. Aggression increases in smaller tanks or with similar species.
Compatibility:
Good Tankmates: Robust, fast-moving fish like larger tetras (e.g., emperor tetras, Nematobrycon palmeri), barbs (e.g., golden barbs, Puntius sachsii), danios, or rasboras. Mid- to top-dwelling fish that avoid their territory are ideal.
Avoid: Other bottom-dwellers or similar-shaped fish (e.g., Rainbow Sharks, Epalzeorhynchos frenatum, loaches, or Corydoras like Corydoras sterbai). Avoid slow-moving, long-finned fish (e.g., guppies, bettas), delicate species (e.g., glass catfish, Kryptopterus bicirrhis, or Otocinclus), and invertebrates like shrimp, which may be harassed.
Social Needs: Best kept singly due to their territorial nature. Housing multiple Red Tail Sharks requires a very large tank (100+ gallons) with ample hiding spots and territories to reduce aggression.
Reproduction
Breeding Red Tail Sharks in captivity is extremely rare and poorly documented:
Breeding Setup:
- Tank: A large (50+ gallon) breeding tank with soft, slightly acidic water (pH 6.5–7.0, 5–10 dGH) and temperature around 77–80°F.
- Conditions: Include caves, robust plants (e.g., Java moss), and smooth surfaces for potential egg-laying. Dim lighting and strong filtration are essential.
- Group: Use a 1:1 male-to-female ratio. Males are slimmer with brighter red tails; females are rounder and slightly duller.
Spawning Process:
Spawning is rarely observed but may be triggered by pristine water, a varied diet (live foods), and stable conditions.
Females may lay adhesive eggs in caves or on plants, which males fertilize, but specific egg counts and hatching times are undocumented.
Eggs, if laid, likely hatch in 2–5 days at 78°F, based on similar species.
Egg Care: Remove adults post-spawning to prevent egg predation. Maintain excellent water quality and consider antifungal treatments like methylene blue.
Fry Care: If successful, feed fry infusoria or liquid fry food, transitioning to baby brine shrimp or crushed flakes. Fry are likely delicate and require pristine water.
Challenges: Breeding is nearly impossible in home aquariums due to their territorial behavior and specific requirements. Most Red Tail Sharks in the trade are commercially bred or wild-caught.
Additional Tips
- Observation: Monitor for signs of stress or aggression (e.g., excessive chasing, faded colors, or hiding).
- Quarantine new fish and acclimate slowly to prevent shock.
- Enrichment: Provide caves and varied decor to establish territories and reduce aggression. Ensure sufficient space to minimize conflicts.
- Health Concerns: Susceptible to ich, fin rot, or stress-related illnesses, often due to poor water quality or tankmate conflicts. Treat with aquarium-safe medications and address underlying causes.
- Territorial Management: Use ample hiding spots or tank dividers in community tanks to reduce aggression toward tankmates.
Picture for illustrative purposes only. Either come in store to view available stock or request pictures to be sent to you.
Please Note: Due to variations within species resulting from age, region, sex, etc., the actual livestock may not look identical to the image. Approximate size range may also vary between individual specimens.
