Myth or Fact: Do Bristlenose Catfish Eat Other Fish in Your Tank?

Bristlenose catfish, sometimes called bristlenose plecos or bushynose plecos, are popular bottom-feeders for freshwater aquariums. These beautiful fish make excellent additions to an aquarium cleanup crew, but how well do these fish get along with other species?

Plecostomus have a reputation for becoming aggressive as they age and grow. Some aquarium hobbyists have even reported their plecos attaching to or feeding on other fish.

Here’s what you need to know about bristlenose catfish and whether you need to worry about them eating other fish in your tank.

Bristlenose Catfish Facts

Bristlenose catfish are members of the Loricariidae family, the largest family of catfish that contains nearly 700 species. They belong to the genus Ancistrus, named for the Greek word agkistron which means “hook.” The name refers to the bushy, tentacle-like projections that grow from the snout in adult males.

Aside from their bristles, Ancistrus species look similar to other Loricariid catfish including the common plecostomus (Hypostomus plecostomus) or pleco. They have flat bellies and wide heads that taper towards the tail. Their bodies are covered in bony plates and their fins are wide and fanlike.

What sets bristlenose catfish apart from the typical Loricariid catfish is its short body. Ancistrus species only grow 4-6 inches long and their bodies are wider and flatter than the common pleco.

There are over 70 species of bristlenose catfish, though some are more popular than others among aquarium hobbyists. When bristlenose catfish first entered the aquarium trade, the two primary species available were Ancistrus cirrhosus and Ancistrus temminckii. Today, bristlenose catfish are available in a variety of colors and patterns including albino and long-finned varieties.

Temperament and Tank Mates

Many aquarium hobbyists appreciate the bristlenose catfish for its limited size but temperament is important to consider as well. Common plecos grow up to 20 inches in length and they tend to become aggressive as they outgrow other fish in the tank. Bristlenose catfish usually don’t grow beyond 5 inches in length.

Though bristlenose catfish are much smaller than common plecos, they can become territorial as they mature. Aggressive behavior is usually limited to other males of the same species, however. Bristlenose catfish can generally be kept with peaceful tank mates, including other algae eaters like bottom-feeders and snails.

While Loricariid catfish are usually only aggressive with others of their kind, some aquarium hobbyists report their plecos attaching to or seeming to feed on other fish in the tank. It’s completely natural for these fish to feed on dead or dying fish they find on the bottom of the tank, but they generally won’t attack healthy fish. The risk is even lower for smaller species like bristlenose catfish.

Setting Up a Bristlenose Catfish Tank

Bristlenose catfish are found throughout South America and Panama in freshwater habitats. They tend to inhabit rivers and floodplains, so they’re used to flowing water. These fish prefer planted tanks with sand, gravel, or aqua soil for substrate.

Though bristlenose catfish stay smaller than most plecos, they still need plenty of tank space. A minimum of 20 gallons is recommended, though 40 gallons is better—especially if you’re cultivating a community tank with other fish.

Proper filtration is a must to maintain high water quality and an aquarium heater is recommended to keep the temperature stable. That said, bristlenose catfish tend to be pretty hardy and adaptable to a range of different conditions. Most specimens available in the aquarium hobby are captive-bred, so mimicking their native habitat is less crucial.

The ideal tank parameters for bristlenose catfish are:

  •       Temperature: 73°F to 80°F
  •       pH Level: 6.5 to 7.5
  •       KH: Under 20 dKH
  •       Tank Size: 20 gallons minimum

How you decorate a tank for bristlenose catfish is important. Like other Loricariid catfish, bristlenose catfish are nocturnal—they’ll need places to hide during the day. Planted tanks are ideal with driftwood and rock caves to provide hiding places. Having hiding places is particularly important if you use bright lighting in your tank to grow plants.

Do bristlenose catfish eat other fish in the tank?

Feeding Bristlenose Catfish

In the wild, bristlenose catfish are primarily herbivores that feed on algae and decaying plant matter. They’ll still eat these foods in the home aquarium, but they may branch out a little more and accept a variety of foods. Supplement natural algae and biofilm growth with sinking wafers or pellets formulated for bottom feeders. Your fish may also enjoy blanched vegetables on occasion.

Providing your catfish with a varied diet is important for long-term health. Bristlenose catfish can live up to 12 years when properly cared for. It’s generally easy to tell whether their nutritional needs are being met by looking at their color—strong coloration is a sign of optimal health.

Breeding Tips for Bristlenose Catfish

Bristlenose catfish are relatively easy to breed and even easier to sex. While females may grow tentacles on their snouts as well, these growths are much larger and more prominent in males. Male bristlenose catfish also tend to be larger than females and may develop spikes on their fins.

In a well-maintained tank, bristlenose catfish typically don’t need much provocation to breed. Make sure your fish are well-fed and keep the conditions as stable as possible until your fish mature. To stimulate breeding, perform a 75% water change—ideally in alignment with the natural mating season that starts in November.

When your fish are ready to breed, the female will lay her eggs somewhere in the territory the male has claimed. Eggs are usually deposited on hard surfaces like rocks, driftwood, or even the filter intake. Male bristlenose catfish guard their eggs until they hatch—usually after 5-10 days. The fry will absorb the remainder of their yolk sacs for a few days and then start feeding on algae and biofilm in the tank.

If you’re looking for a community-friendly algae eater for your freshwater aquarium, the bristlenose catfish is a great option to consider. They’re generally peaceful fish and their unique appearance and nocturnal activity make them a joy to keep.


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