Red Fin Shark: Fish Species Profile

The Red Fin Shark (also known as the Red-Finned Rainbow Shark or Red-Finned Shark) is a striking freshwater fish with an eye-catching appearance, known for its vibrant red fins and sleek, shark-like body. This species is popular among aquarium enthusiasts for its active behavior, unique coloration, and its ability to add a dynamic flair to community tanks. Despite the name “shark,” it is not a true shark, but rather a species of cyprinid.

• Common Names: Red Fin Shark, Red-Finned Rainbow Shark, Red-Finned Shark
• Scientific Name: Epalzeorhynchos frenatum
• Adult Size: Typically 6 to 8 inches (15 to 20 cm) in length
• Life Expectancy: 5 to 7 years in a well-maintained tank

Characteristics

The Red Fin Shark features a slender, streamlined body with dark hues and distinctive red fins, making it stand out in any aquarium. Its body is typically a dark, grayish or olive green, and its fins – especially the dorsal and caudal fins – are a bright, striking red. Known for its active nature, this fish prefers to swim in the middle to lower levels of the tank and often displays territorial behavior, particularly with other fish that look similar or encroach on its space.

• Family: Cyprinidae
• Origin: Native to Southeast Asia, particularly in rivers and lakes in Thailand, Laos, and Cambodia
• Social Behavior: Semi-aggressive; territorial, especially with other rainbow sharks or fish with similar body shapes
• Tank Level: Mid to lower-level swimmers
• Minimum Tank Size: 55 gallons (208 liters)
• Diet: Omnivorous, primarily algae, but will also eat small invertebrates and commercial fish food
• Breeding: Not bred in captivity (difficult to breed in an aquarium)
• Care Level: Moderate; suitable for aquarists with some experience
• Water Conditions:
  • pH: 6.5 to 7.5
  • Temperature: 74°F to 79°F (23°C to 26°C)
  • Hardness: 5 to 15 dGH

Origin and Distribution

The Red Fin Shark is native to the freshwater rivers and lakes of Southeast Asia. These fish are typically found in slow-moving, warm waters with moderate vegetation and plenty of hiding spots. While they are commonly bred in captivity for the aquarium trade, wild populations are still found in their native regions.

Colors and Markings

The Red Fin Shark is easily recognizable by its dark, almost black body, contrasted with vibrant red fins. The coloration can range from a deep olive or gray on the body to bright crimson hues on the tail, dorsal, and pelvic fins. The contrast between the body and fins gives this fish its distinctive, shark-like appearance. The fins may darken or become more vibrant depending on the fish’s mood and overall health.

Tankmates

The Red Fin Shark is semi-aggressive and tends to be territorial, especially when it comes to other fish that resemble its body shape. While they can be kept with other peaceful species, it is important to ensure enough space for each fish to establish its territory.

• Recommended Tankmates:
  • Peaceful, non-aggressive fish such as tetras, gouramis, or danios
  • Bottom-dwelling species like Corydoras catfish or plecos
  • Larger peaceful species like angelfish or rainbowfish
• Fish to Avoid:
  • Other rainbow sharks, as they are territorial and may fight
  • Smaller, slow-moving fish that might be seen as prey or get bullied
  • Aggressive or similarly territorial species

Habitat and Care

The Red Fin Shark requires an aquarium with plenty of space for swimming and establishing territory. Providing hiding spots with plants, rocks, and other decorations is important to reduce stress. These fish thrive in slightly acidic to neutral water with regular water changes to maintain water quality. Good filtration is also essential due to their active nature.

• Ideal Aquarium Conditions:
  • A tank with plenty of swimming space and hiding spots
  • Moderate to strong filtration to maintain water quality
  • Stable water parameters with a pH range of 6.5 to 7.5
  • A sandy or gravel substrate, as they enjoy digging through it

Diet and Feeding

The Red Fin Shark is omnivorous and enjoys a varied diet. In the wild, they feed on algae, small invertebrates, and plant matter. In the aquarium, they can be offered a variety of foods, including algae wafers, flake food, and occasional live or frozen food such as brine shrimp or bloodworms. Supplementing their diet with vegetable matter such as blanched zucchini or spinach will help ensure they remain healthy.

• Feeding Tips:
  • Feed 2-3 times a day in small amounts
  • Provide both plant-based foods (like algae wafers) and protein (like live or frozen foods)
  • Remove uneaten food after 5-10 minutes to prevent water quality issues
  • Offer a balanced diet to maintain vibrant colors and overall health

Gender Differences

Males and females are very similar in appearance, but there are subtle differences. Males are typically smaller and more colorful, particularly when they are displaying during mating behavior. Females are generally rounder and larger, especially when carrying eggs, though they lack the same vibrant coloration as males.

• Male: Smaller, more colorful with brighter red fins, more slender body
• Female: Larger, rounder, less vivid in coloration

Breeding

Breeding Red Fin Sharks in captivity is quite rare, as it requires very specific conditions. They are egg layers, but like many fish species, the breeding process in captivity can be difficult to replicate. In the wild, the males display to the females, and once fertilized, the eggs are laid and hatch in a relatively short period. However, it is uncommon to successfully breed them in a home aquarium.

• Breeding Tips:
  • Red Fin Sharks require a breeding pair in a well-maintained tank with stable water conditions
  • Provide adequate space and hiding spots to reduce territorial stress
  • Use a separate breeding tank if possible, as the eggs are vulnerable to being eaten by other fish

More Pet Fish Species and Further Research

If you enjoy the Red Fin Shark, you may want to consider other types of active, colorful fish with similar care requirements, such as other species of rainbow sharks or larger schooling fish. Exploring peaceful but active tank mates for a community tank can enhance the dynamic of your aquarium.

FAQ

Q: How many Red Fin Sharks should I keep together?
A: It’s best to keep only one Red Fin Shark per tank, as they can be territorial with other sharks or similar species. If keeping more than one, make sure the tank is large enough to give each fish space.

Q: Are Red Fin Sharks hard to care for?
A: No, they are moderately easy to care for but require a spacious tank with good filtration, stable water parameters, and a varied diet. They are best suited for intermediate aquarists who are familiar with managing semi-aggressive species.

Q: How can I tell if my Red Fin Shark is male or female?
A: Males are typically smaller and more colorful, especially during courtship, while females are larger and rounder, particularly when gravid (carrying eggs)