With their bright red tails and shark-like appearance, red tailed sharks tend to frighten some aquarium owners. But are these freshwater fish actually aggressive? In this comprehensive guide, we’ll provide a detailed look at red tailed shark behavior and aggression levels to help you determine if this fish is right for your tank.
If you’re short on time, here’s a quick answer: Red tailed sharks can exhibit aggressive behavior, especially toward other bottom-dwelling fish, but they are not extremely aggressive by nature and can live peacefully in a well-designed community aquarium.
We will cover topics like the natural behavior of red tailed sharks, signs of aggression, ideal tank conditions to curb aggression, tank mates that are compatible with red tailed sharks, and more to provide a complete picture of this fish’s temperament.
Natural Behavior of Red Tailed Sharks
Territorial by Nature
Red tailed sharks, scientifically known as Epalzeorhynchos bicolor, are notoriously territorial fish. They establish a territory in the aquarium and defend it aggressively from other fish. Red tails may chase, nip fins, and ram into other fish that invade their space.
Though medium-sized, red tails act like they are 6 inches long! They bravely defend their turf from much larger tankmates.
To curb aggression, provide a spacious tank of at least 55 gallons with plenty of hiding spaces and sight breaks. Red tails claim cave-like decor as their lair and retreat there when stressed. Aquascaping the tank into different territories can also diffuse territorial disputes.
Bottom Dwellers
In the wild, red tailed sharks inhabit fast flowing streams in Southeast Asia. They frequent riverbeds, rooting around the substrate for food. These sharks are built to live and forage near the bottom. Their eyes point downward to spot food and potential threats along the floor.
Similarly, red tails utilize the tank bottom in home aquariums. They spend most of their time skimming above the gravel looking for morsels to eat. Floating flakes and pellets often go ignored. Instead, red tails prefer sinking wafers, tablets, and frozen foods like bloodworms and brine shrimp.
Keep this in mind when feeding!
Omnivorous Diet
Red tailed sharks are omnivores, meaning they eat both plant and animal matter. Their diverse diet includes:
- Algae
- Aufwuchs
- Detritus
- Insects
- Crustaceans
- Larvae
In the aquarium, red tails readily accept veggie-based foods like spirulina and algae wafers along with meaty options. A high quality flake or pellet along with supplemental feedings of frozen and live foods provides balanced nutrition.
This species has a big appetite and fast metabolism. Feed juveniles 2-3 small meals daily and adults at least once daily. Avoid overfeeding, as these sharks are prone to obesity if overfed.
Signs of Aggression in Red Tailed Sharks
Flaring Fins
One of the most common signs of aggression in red tailed sharks is flaring their fins. When feeling threatened or territorial, red tails will fully extend their dorsal and pectoral fins to make themselves look larger and more intimidating to potential rivals.
This behavior is often accompanied by changes in color, where their shades darken for a bold warning display. If you notice your red tail shark flaring its fins frequently, it likely feels stressed by tank mates competing for space and resources.
Chasing Tank Mates
Red tailed sharks that relentlessly chase other fish in the aquarium are showing domineering behavior. They will zoom around the tank in hot pursuit of any fish they perceive as a threat. Targets are most often bottom-dwellers, like plecos and loaches, which venture into the shark’s claimed territory.
But chasing may also result from extreme hunger, if the red tail is denied an adequate diet. Provide plenty of suitable tank decor like caves and driftwood to break up line of sight. And feed red tails 2-3 small meals per day rather than one large meal.
Claiming Territories
As highly territorial fish, red tailed sharks will claim and defend certain areas of the tank as their own. These zones typically include hiding spots and the bottom level of the tank. Red tails will become aggressive to scare away intruders.
They may perform threat displays, chase after fish, or even nip fins and attack if provoked. To curb territorial behavior, create a spacious aquarium of at least 55 gallons with plenty of sight breaks. Adding more sharks can also spread aggression.
Limit tank mates to those able to handle themselves against a pushy shark.
Tank Conditions That Prevent Aggression
Tank Size
Red tail sharks originate from fast-flowing streams in Thailand. In the wild, they have a large territory which allows them to establish distinct hierarchies and avoid conflict. Replicating similar conditions in an aquarium is key to curbing aggression.
These fish need a minimum tank size of 55 gallons. However, a larger tank of 75-125 gallons is ideal as it allows more swimming space and territorial claims. The more room red tail sharks have, the less likely they are to skirmish over territory.
Aquascaping and Hiding Places
Aquascaping the tank with rocks, driftwood, and plants can help diffuse aggression. These elements break up lines of sight and allow fish to establish their own domains.
Be sure to include many hiding places like caves and tunnels. With sufficient shelters, less dominant fish can retreat when confronted and avoid altercations.
Water Parameters
Maintaining pristine water quality helps curb aggression in red tail sharks. Key parameters to monitor include:
- Temperature: 74°F – 79°F
- pH: 6.5 – 7.5
- Hardness: 5 – 15 dGH
Test the water weekly and perform partial water changes as needed to keep levels in check. Clean, well-oxygenated water reduces stress and conflict.
Compatible Tank Mates for Red Tailed Sharks
Fast-Moving Schooling Fish
Schooling fish like tetras, danios, rasboras, and barbs make great tank mates for red tailed sharks. These fish are very active and fast moving, so they rarely get bullied or chased by the shark. Plus, their schooling behavior and bright colors provide interesting activity in the tank.
Some good options include neon tetras, harlequin rasboras, zebra danios, cherry barbs, and black skirt tetras. Just be sure to get at least 6-8 individuals of each species so they feel secure in a proper school.
Large Semi-Aggressive Species
Certain large semi-aggressive fish are big and tough enough not to be intimidated by an adult red tailed shark. Examples include silver dollars, rainbowfish, Pearl Gourami, Angelfish, grouper, Oscar fish, Green Terror, Jack Dempsey, Convict Cichlid, and Firemouth Cichlid.
These fish add beauty and personality to the aquarium while holding their own against the shark. However, monitor during feeding time as competition could arise over food. Also be sure the tank is large enough (75+ gallons) to allow plenty of territory for each fish.
Bottom Feeders That Won’t Compete for Territory
Bottom dwelling fish that don’t compete for territory work well with red tailed sharks. Good options include plecos, cory catfish, loaches, and Synodontis catfish. These fish occupy the lower tank region searching for food while the shark patrols the middle and upper levels.
For example, Bristlenose and Clown pleco stay under 6 inches long and help clean algae off decorations. Cory cats like Green, Bronze, and Peppered search the substrate for leftovers. YoYo loaches and Synodontis eupterus add interesting behaviors like playing dead or upside-down swimming.
Provide plenty of caves and driftwood so bottom dwellers have hiding spots when needed.
Conclusion
While red tailed sharks can display aggressive tendencies, especially toward fish that inhabit the tank bottom, they are relatively peaceful compared to other semi-aggressive aquarium fish when provided with an adequately sized tank and some compatible tank mates.
By understanding their natural territorial and bottom-dwelling behaviors and meeting their needs, red tailed sharks can thrive in a peaceful community tank. Their stunning red tails still make them a popular freshwater choice when the tank is properly equipped to handle their temperament.
