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Are Columbian Sharks Aggressive?

Often referred to as the silver tipped shark, the Jordan’s catfish, or the west American cat shark, the Columbian shark is a type of brackish water fish that many aquarium hobbyists enjoy keeping. But what about their temperament? Are Columbian sharks aggressive? The answer is no, let me explain why…

Regarding disposition, Columbian sharks are generally peaceful, yet predatory in nature and may eat smaller tank mates as they grow larger. If alone in an aquarium that’s too small, Columbian sharks can become stressed or anxious. Therefore, they should be kept in a school of 3 in big, 100-gallon tank.

Now that you know Columbian sharks are usually docile when kept with others of their kind in the appropriate aquatic environment, let’s explore this topic in more detail. I’ll explain what Columbian sharks like to eat, what type of water conditions they prefer, and which fish make the best tank mates.

So, if you’re ready to learn more about the unique and illusive Columbian shark and their behavior in captivity, then let’s begin!

What Can Lead to Aggression in Columbian Sharks?

Though Columbian sharks tend to be docile and passive in temperament, there are circumstances that can potentially lead to aggression when kept in a captive environment. These include the following:

  • if the aquarium is too small and they have an urge to compete for space
  • if not fed enough and they feel the need to fight for food
  • if kept alone (with no other fish of their species) and they feel tense
  • if sick or dying and they come across another fish that’s sick or dying
  • if the water parameters are ‘off’ and they feel stressed

Please note that Columbian sharks are highly active, fast swimmers and their speed can sometimes be mistaken for aggression. They’re also nocturnal and ‘come alive’ at night. This is normal and natural for this species and unless other fish appear to be in danger, there’s no need for concern.

How to Prevent Aggression in Columbian Sharks?

Columbian sharks are not usually aggressive in a community tank environment. That said, the best ways to maintain their natural sense of calm and reduce stress include the following:

  • make sure to feed them adequately – once a day (or maybe twice, depending on how big they are and how many you have) is often sufficient
  • keep them in as a large and wide a tank as possible – bigger is always better when it comes to aquarium size for Columbian sharks
  • ensure the water conditions are accurate and consistent with a brackish aquatic environment
  • provide areas of cover as well as plenty of open space for swimming
  • add a blue ambient light to tank to simulate moonlight and encourage safe evening foraging

As well, consider ‘aquascaping’ your aquarium to help decrease tension in a community tank with Columbian sharks. Adding artificial plants in a variety of shapes and colors not only adds visual interest, but they also provide hiding places for fish without altering the water parameters.

What Type of Water do Columbian Sharks Prefer?

Columbian sharks (which aren’t actually a species of shark at all) are widespread along the Eastern Pacific. Residing in brackish rivers and coastal waters near Central and South America, this catfish needs very specific water conditions to thrive in a captive environment.

Regarding water parameters, Columbian sharks prefer brackish conditions. Despite them usually being sold as type of freshwater fish, Columbian sharks do best in hard water with low salinity.  A pH level between 7.0 an 8.0 is recommended along with a temperature of 75 to 80 degrees Fahrenheit.

Since brackish water is the ‘middle ground’ between freshwater and saltwater conditions, the tank will need to be set-up accordingly. Use marine salt to create the proper salinity level in the tank, which is typically somewhere between 1.005 and 1.012 and treat tap water with a water conditioner as well.

What do Columbian Sharks Like in Their Tank?

Creating the proper tank conditions for Columbian sharks go beyond water parameters. A substrate of crushed coral sand or gravel helps maintain the right pH and alkalinity levels. Artificial instead of live plants can also be added since many aquatic plants won’t survive in water with high salt concentrations.

Avoid adding driftwood, if possible, since it can lower both the pH and alkalinity of brackish water. Add caves or rocks for cover but make sure there’s still ample room for fish to swim about freely. Columbian sharks are quite active and need space to move!

What is the Best Tank Size for Columbian Sharks?

Columbian sharks can grow to be quite large. Reaching lengths of up to 20 inches in length, this species needs a big tank to thrive in a captive aquatic environment. Minimum tank size is 75-gallons, and that’s just for a single Columbian shark!

Since this species prefers the company of others Columbian sharks, they should be kept in groups of at least 3 (2 females and 1 male), if possible. Given their large size and active nature, a 100-gallon tank or preferably larger (between 150 and 200 gallons) is recommended.

What do Columbian Sharks Eat?

Columbian sharks are a type of catfish and therefore are omnivores as well as scavengers. When in captivity, they’ll often forage throughout the day, picking at pieces of uneaten food that settle along the substrate at the bottom of the tank.

For optimum nutrition, Columbian sharks should be fed a combination diet of both plant- and meat-based foods. Fish flakes and pellets along with frozen brine shrimp and blood worms are ideal. As well, they need only be fed twice a day with just enough food that can be ingested in a 5-minute time-period.

How Fast do Columbian Sharks Grow?

Columbian sharks can grow to be quite large – up to 15 inches in length or more – under the proper aquatic conditions. Nutritional food, the correct brackish water conditions, and a large tank are a just few examples.

On average, Columbian sharks when well cared for can grow anywhere from ½ to 1 inch per month! Once they reach a length of 8 to 10 inches, the rate of growth starts to taper off. The bigger the tank, the larger the fish. If kept in a 200-gallon tank, this species has the potential to grow up to 20 inches!

What are the Best Tankmates for Columbian Sharks?

Since Columbian sharks are generally peaceful in nature, they can be kept with a variety of aquarium creatures, provided they’re not too small, that is. Little fish like guppies, for example, can fall prey to this large, very active species.

Keeping Columbian sharks with other docile, brackish water fish is recommended. These include archers, gobbies, mollies, monos, puffers, reeds, scats and target fish. As they tend to stick close to the bottom of the tank, they won’t often disturb other fish that like to swim about near the surface.

As a type of catfish, Columbian sharks can also be kept with other catfish species including clariid, pictus and siluridae. Just make sure to have a large enough tank so fish have enough space to forage and swim freely. An overpopulated aquarium leads to an increase in stress and tension among its inhabitants.


To conclude, Columbian sharks are usually docile in nature, provided their kept with others of their kind in an aquarium environment conducive to that of ‘the wild’. A large, brackish water tank reminiscent of their natural habitat is needed for Columbian sharks to not only survive but thrive in captivity.

I trust this article has provided you with the information you seek regarding Columbian sharks, their temperament and how to care for them. Thanks for reading and good luck with your aquarium hobby.

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