Red tail shark

Overview

The red tail shark is a cyprinid from Thailand with a velvety black body and a bright red tail. Its tall dorsal fin gives it a mini-shark silhouette, and it is one of the most striking fish you'll see in a store.

Oddly enough, it is critically endangered in the wild: it was once thought extinct in its native river because of dams and habitat loss, while Asian fish farms produce it by the millions. It is hardy but has attitude. It claims a territory on the bottom and won't tolerate others of its kind or similar-looking fish. It's best for hobbyists who plan their stocking carefully.

Care and tank setup

One adult needs a tank at least 48 inches long, about 55 gallons (200 liters). Floor space is what counts: the more bottom area it has, the less it chases everyone else.

• One per tank: two red tails, or a red tail and a rainbow shark, means nonstop fighting, often with one badly stressed loser.
• Decor: caves, driftwood, rocks and plants that break up sight lines and give it a clear territory.
• Water: clean, well filtered and oxygenated, with some flow and weekly water changes.
• Lid: they can jump.
• Tank mates: fast mid- and top-water fish such as danios, barbs or rainbowfish rather than other bottom dwellers.

They tend to harass corydoras, loaches and small plecos, and get more territorial with age. Avoid fish with similar colors or body shapes. Shrimp are a bad idea.

Feeding

An omnivore that spends the day grazing biofilm and algae off rocks and wood. Offer sinking wafers and pellets with a good plant component (spirulina, blanched veggies), plus bloodworms, brine shrimp or daphnia. Make sure food reaches the bottom and that it doesn't hog everything meant for other bottom feeders.

Breeding

They don't breed in home aquariums. Aggression toward their own kind makes keeping a pair nearly impossible, and spontaneous spawnings are virtually unheard of. Store fish are raised on Southeast Asian farms, usually with hormone-induced spawning. That's one more reason to buy only captive-bred fish, never wild-caught.

Compatible tank mates

Species from our database that share water parameters, size and temperament with the Red tail shark. Calculated from the data in each profile.

Check the compatibility of your whole tank →

What not to keep it with

Popular species you shouldn’t house with the Red tail shark, and why.

• Discus: incompatible temperatures
• Otocinclus catfish: one may eat the other due to size
• Celestial pearl danio: one may eat the other due to size
• Ember tetra: one may eat the other due to size
• Neon tetra: one may eat the other due to size
• Amano shrimp: eats shrimp
• Cherry shrimp: eats shrimp

Recommended equipment

What you need to keep the Red tail shark healthy, checked against Amazon stock.