The Red Tail Shark ( Epalzeorhynchos bicolor ) is a captivating freshwater fish admired in the aquarium hobby for its striking appearance and dynamic behavior. With a jet black body sharply contrasted by a vibrant red tail, the red tail shark makes a visually appealing addition to any aquarium. Despite its common name, it is not a true shark but belongs to the Cyprinidae family, which includes Carps and Minnows.
Once found inhabiting streams throughout Thailand, the red tail shark was declared extinct in the wild in 1996 after decades of habitat loss. Despite this, it is widely available in the aquarium trade and is bred commercially in large numbers.
Appearance and Size
The appearance of the Red Tail Shark is pretty straightforward. One of the reasons why this fish is so striking is the sudden change in color from black to red. Right at the end of the caudal peduncle, the color shifts from black to bright red. It doesn’t shift gradually either. On their caudal tail, this red color is steady throughout. As juveniles, the Red-Tailed Black Shark is jet black with a bright red caudal fin, but as they mature, their colour fades to a dark grey.
Their bodies look very much like sharks (even though they technically aren’t). Their dorsal fin begins roughly halfway back on their body and resembles the classic trait of the scary fish we’ve come to fear in movies. Their chunky torpedo-shaped body and dorsal fin halfway down their back give them a striking shark-like appearance that is sure to impress.
The average Red Tail Shark size is between 4 and 6 inches when fully grown. Most red tail sharks will grow to 6 inches (15.2cm) in length, but it’s not unusual for a shark to reach 7 (17.8cm) or even 8 inches (20.3cm) in length. In our experience, this species will typically end up being on the higher end of that range as long as you’re giving them proper care.
Read also: Comprehensive Bala Shark Guide
Lifespan
The average Red Tail Shark lifespan is between 5 and 8 years. Among them are buying your fish from a reputable seller, keeping them in a great habitat, and reducing stress by keeping them with the proper tank mates.
Aquarium Setup
Red Tail Shark care is often misunderstood by many aquarists. These fish are pretty straightforward and easy to care for as long as you know the basics. With that being said, if you set them up with an insufficient tank you’ll definitely have some problems.
Tank Size
The recommended tank size for Red Tail Sharks is 55 gallons. This space also comes in handy for reducing the possibility of aggressive behavior. Others, like bala, black, harlequin and Colombian sharks can reach over 12" in length and will require an aquarium of at least 100 gallons when full grown. It should be pointed out that Chinese banded and red-finned cigar sharks can achieve 36", and iridescent sharks exceed 48" in nature. These fish should not be kept in home aquariums. (The notion that fish grow to the size of their habitat is false.)
Water Parameters
Water parameters are an element of Red Tail Shark care that you won’t have to worry much about. Freshwater sharks tolerate a wide range of water quality parameters in the aquarium. For best results, pH should be between 6.8 and 8.0, with hardness between 2° and 10° dKH (35 to 175 ppm). Colombian or hi-fin sharks prefer slightly higher pH and alkalinity and benefit from the addition of up to 1 tablespoon of aquarium or sea salt per gallon. Before adding salt to any aquarium, make sure other inhabitants are tolerant of it! Temperature for most sharks should be 74° to 80° F. The exception is the Chinese banded shark, which can be kept at temperatures as low as 60° F.
Even though these aren’t the most sensitive species in the world, you should always check the water parameters on a consistent basis. Invest in a solid aquarium testing kit to make sure the readings you’re getting are accurate.
Read also: What do reef sharks eat?
Maintain good filtration and do a 10% water exchange every week or 25% every 2 weeks using an Aqueon Aquarium Water Changer or Siphon Vacuum Gravel Cleaner. Don't forget to treat tap water with Aqueon Water Conditioner before refilling your aquarium!
Habitat
Setting up a good Red Tail Shark habitat is pretty simple once you understand their native environment. As we mentioned earlier, this fish comes from the largest lake and swamp area in central Thailand. This means you should include these items if you want your fish to be comfortable. Enhancing the aquarium with an arrangement of rocks, pebbles, and driftwood, complemented by resilient aquatic flora, affords numerous concealment spots for your fish, contributing to their sense of security and well-being. Emulating their indigenous environment through the creation of a stream or river-like setting, complete with a substrate of sand or fine gravel and interspersed with boulders, represents an optimal setup.
Any durable and reasonably-sized plants like hornwort or water wisteria will work well. Some driftwood is a good inclusion that will provide some variety and places for fish to hide. Make sure there’s enough room to swim after adding everything. The ideal substrate for Red Tail Sharks is moderately-sized gravel or pebbles.
Red tail sharks don’t have any special filtering requirements, and a good HOB (hang-on-back) filter will normally be more than adequate. If choosing an HOB filter, I would strongly recommend choosing an Aquaclear Power Filter for a red tail shark tank. This filter combines excellent filtration with a durable design, and it will keep your tank sparkling clear for years to come.
Most freshwater sharks are accomplished jumpers, so keep a secure lid on the aquarium.
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Diet and Feeding
Ensuring a nutritious and well-rounded diet is critical for the health and vivid coloration of the Red-tailed Black Shark. In the wild, red tail sharks primarily feed on plant matter, but also eat worms, crustaceans and small insects.
You can tell a lot about a fish's diet by looking at its mouth parts. Sharks with sucker-type mouths typically rasp algae off rocks and submerged wood, and feed on plants, as well. Other foods include aquatic invertebrates, worms and small fish. Iridescent and Colombian sharks, with their wide cavernous mouths, are predatory and will not hesitate to eat small fish and/or shrimp. Most sharks are omnivorous in captivity and will thrive on a varied diet.
You have a lot of options when it comes to Red Tail Shark food. In their natural habitat, they eat plants, insects, and various crustaceans. Most owners feed this species flakes or pellets as the primary source of nutrition. A foundation of their nutritional regimen should be high-quality dry foods, including flakes, granules, and pellets. In the home aquarium, they should be offered a high quality plant based flake or pellet food, along with a normal high quality flake food.
You can also throw in some other foods for the sake of variety and enrichment. To complement this, incorporating live and frozen options, such as bloodworms, daphnia, mosquito larvae, and brine shrimp, is imperative for providing a comprehensive spectrum of essential nutrients. As a treat, they can also be feed frozen foods. They also appreciate vegetable matter in their diet, and aside from grazing on algae, they should be fed blanched zucchini medallions, cucumber medallions and shelled peas. Given their natural propensity for algae grazing, the inclusion of plant-based supplements, like spirulina or algae wafers, is recommended.
For best results, rotate your fish's diet daily and feed only what they can consume in 2 to 3 minutes, once or twice a day. Because Red Tail Sharks aren’t picky eaters, it’s important to make sure you’re not overfeeding them. Also, keep an eye on how much food is actually being eaten and how much is falling to the substrate.
Tank Mates and Temperament
Red-tailed Black Sharks exhibit pronounced territorial behaviors, necessitating solitary housing in smaller aquariums to prevent conflicts, especially with species of similar appearance. Optimal conditions for maintaining these fish involve grouping them within a spacious, intricately arranged habitat.
Red tail and rainbow sharks become territorial as they grow and should be provided with plenty of space as well as caves and other structures to call "home". Red tail and rainbow sharks become territorial, especially toward one another and are best kept individually when they get older. They will patrol the entrance to their lair and chase intruders away.
When selecting companions for Red-tailed Black Sharks, it is advisable to choose larger, vigorous, and sturdy schooling fish from the Cyprinid family, including species like Mascara Barbs, Denison Barbs, Odessa Barbs, and Clown Barbs. Tank mates should be robust and include active fish like giant danios, silver dollars, tinfoil barbs, medium sized non-aggressive cichlids, larger loaches and large gouramis.
It is crucial, however, to steer clear of species with similar appearances, such as the Rainbow Shark and True Flying Fox. Fish that look similar should not be kept in the same tank. A great example of this is the Rainbow Shark. Thai flying foxes (Crossocheilus spp.) and bala sharks (Balantiocheilos melanopterus) are more peaceful and can be kept with community fish that are similar in size.
The Red Tail Shark is very territorial and can be overly aggressive, especially to their species and fish of a similar appearance, such as the Rainbow Shark, Sliver Flying Fox and some algae eating loaches. It is recommended to house these fish with other semi-aggressive fish or ensure the aquarium is large enough for the other fish to escape harassment. In keeping with other shark type species ensure there is a group, so the aggression is more distributed instead of focused on a single fish.
Red Tail Sharks are a very active fish that are a lot of fun to watch. This activity level is why it’s so important to give them an adequate tank size and set their habitat up properly. Any aggressive tendencies they display will be exaggerated by insufficient space or the wrong tank mates. Fish that are overly curious, aggressive, or bottom-dwellers aren’t a good fit for them. Fish that will mind their own business and spend more of their time in the upper half of the aquarium are compatible.
While red tail sharks can be aggressive to their tank mates, they will rarely bite or damage the other fish. However, because guppies sleep on the bottom during nighttime, you may find their fins nipped occasionally. The red tail shark is an omnivore, so it could predate on smaller shrimp, so if you plan to breed your shrimp, you should avoid Red Tail sharks and, in general, avoid the addition of all fish to your aquarium for the highest yield. Because Amano shrimp does not reproduce in freshwater and is more significant than most other aquarium shrimp types, these are your safest option.
While it’s definitely possible to keep more than one Red Tail Shark in the same aquarium, it comes with risk. In order to get around this, it’s recommended to have a few of them in the same tank instead of two. However, this also means you’ll need to get a fairly massive tank.
Common Diseases and Prevention
The most common are Ich and fin rot. Our recommendation is to focus on prevention rather than being paranoid about treatment. Until then, do your best to feed your Red Tail Shark great food and provide them with a top-notch habitat. You should also spend a few minutes each day inspecting your fish. Take a close look to see if you notice anything out of the ordinary on their body (or in their behavior).
Breeding
Not much is known about red tail sharks breeding habits, and it is extremely rare to have them breed in a home aquarium. There is currently no information available regarding successful breeding of the Red-tailed Black Shark in home aquariums. Very few records of freshwater shark breeding in home aquariums have been reported. Commercial breeders often use hormones to induce spawning of redtail, rainbow and bala sharks.
Breeding attempts (successful or failed) have an impact on the health of your fish and come with risks. If this changes and someone cracks the code we’ll expand this section.
Sexing Red Tail Sharks
It can be challenging to distinguish between male and female Red-tailed Black Sharks when they are immature. However, once they reach maturity, there are some visible differences between the sexes. Typically, the male's caudal fin is brighter than the female's and appears slightly slimmer. Additionally, the males tend to develop longer extensions to their dorsal and anal fins.