Bristlenose Pleco

Ancistrus cirrhosus

Catfish

A highly popular, hardy, and relatively small suckermouth catfish. Excellent algae eaters that stay much smaller than Common Plecos, making them suitable for standard aquariums. They require dietary wood (driftwood) to aid in digestion and plenty of hiding caves.

At a Glance

Adult Size13 cm
Body ShapeDepressed
Growth RateModerate
TemperamentPeaceful
Water TypeFreshwater Only
Flow PreferenceModerate
Waste OutputExtreme
StockingSolo or group

Tank Requirements

Minimum Volume75 L
Minimum Length60 cm
FlowModerate
Water TypeFreshwater Only
Must-Haves in the Tank
Driftwood (Digestion/Hiding)Established Algae (Otocinclus)

Water Parameters

Temperature2227°C
pH67.5
Hardness415 dGH

Temperament & Compatibility

Aggression LevelPeaceful
2/10
Where They Swim
Surface
Mid-level
Bottom
Stocking Guidelines
Keep at Least1 (solo is fine)
Max per TankNo limit
Can Live Alone?Yes
Behavior Traits
Nocturnal

Available Varieties

Each variety inherits the species defaults above. Only differences are highlighted.

Male (Standard / Color Morphs)

Males develop impressive, fleshy tentacles (bristles) on their snout and head. While peaceful to other species, males are highly territorial over caves and breeding sites. Keep only one male unless the aquarium is large (150L+) with broken sightlines.

Differs in 2 traits from base species

Also known as: Male, Standard, Wild Type, Albino, Super Red, Calico

TemperamentMostly Peaceful
Behavior Traits
NocturnalTerritorial (Defends specific area)Aggressive to same species/look-alikes

Female

Females generally lack the prominent head bristles (though some may develop small nubs around the lip margin). They are peaceful towards each other and can be kept in groups or alongside a single male.

Differs in 3 traits from base species

Also known as: Female, Girl, Smooth Snout

Adult Size11 cm
TemperamentPeaceful
Behavior Traits
NocturnalShy / Slow Moving (Easily Stressed)

Longfin Morph

A selectively bred variant featuring long, flowing fins. They require gentler flow to prevent exhaustion and snag-free decor. Avoid keeping with known fin-nippers.

Differs in 3 traits from base species

Also known as: Longfin, Veiltail, Long Finned Bristlenose

Adult Size16 cm
FlowLow
Behavior Traits
NocturnalLong Finned (Nipper Target)Shy / Slow Moving (Easily Stressed)

Bristlenose Pleco Care Guide Summary

The Bristlenose Pleco, scientifically known as Ancistrus cirrhosus, belongs to the Catfish family group. Adults reach a maximum size of approximately 13 cm and have a depressed body shape with a moderate growth rate. Classified as peaceful, this species primarily occupies the bottom zone of the aquarium and produces a extreme level of biological waste.

To thrive, the Bristlenose Pleco requires a freshwater only aquarium with a minimum volume of 75 litres and a tank length of at least 60 cm. Water temperature should be maintained between 22°C and 27°C, with a pH range of 67.5 and a general hardness of 415 dGH. A moderate water flow is preferred.

The Bristlenose Pleco is a rewarding species to keep, provided its core environmental needs are met. This species is available in 3 varieties: Male (Standard / Color Morphs), Female, and Longfin Morph. Each may differ slightly in size, temperament, or care needs, so it is worth checking the specific requirements of the variety you plan to keep.

Bristlenose Pleco Habitat Setup

When setting up an aquarium for the Bristlenose Pleco, a moderate water flow best suits their natural preferences. Because this species occupies the bottom zone, the aquarium layout should prioritise sufficient floor space with hiding spots among rocks, wood, or dense planting. Useful additions include driftwood, which can serve as both a hiding place and a dietary supplement and an established tank with natural algae growth, as they depend on it as a primary food source.

Bristlenose Pleco Compatibility Notes

Classified as peaceful, the Bristlenose Pleco is adaptable and can be kept singly or in a small group, offering flexibility when planning a community tank. Selecting tankmates that favour different water layers from the bottom zone can help reduce competition and territorial overlap.

Frequently Asked Questions About Bristlenose Pleco

How big does Bristlenose Pleco get?+
Bristlenose Pleco (Ancistrus cirrhosus) typically reaches a maximum adult size of approximately 13 cm. They have a depressed body shape and a moderate growth rate.
What tank size does Bristlenose Pleco need?+
A minimum aquarium volume of 75 litres and a tank length of at least 60 cm are recommended for Bristlenose Pleco. This ensures enough swimming space and helps maintain stable water conditions.
What water parameters does Bristlenose Pleco need?+
Bristlenose Pleco thrives in freshwater only conditions with a temperature range of 22–27°C, a pH between 6 and 7.5, and a general hardness of 4–15 dGH. A moderate water flow is preferred.
Is Bristlenose Pleco peaceful or aggressive?+
Bristlenose Pleco is classified as peaceful with an aggression score of 2 out of 10. They are generally well-suited to peaceful community tanks.
Can Bristlenose Pleco live alone?+
Yes, Bristlenose Pleco can be kept singly or in a group. They are flexible and adapt well to both setups.
Does Bristlenose Pleco have any special tank requirements?+
Yes. Bristlenose Pleco benefits from driftwood (digestion/hiding) and established algae (otocinclus) in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.

Similar Species

Common Pleco

Hypostomus plecostomus

Catfish
45 cm Mostly Peaceful

A heavily armored, nocturnal catfish famous for eating algae. However, they grow incredibly large, produce massive amounts of waste, and frequently outgrow standard aquariums. They require driftwood in their diet for digestion. As they age, they may become territorial or develop a taste for the slime coat of slow-moving, flat-bodied tank mates.

Otocinclus

Otocinclus vittatus

Catfish
4 cm Peaceful

A small, peaceful, and highly popular algae-eating catfish native to South America. They are obligate shoaling fish that thrive in mature, heavily planted aquariums with steady water parameters and a constant supply of soft green algae and biofilm. They are extremely sensitive to uncycled or pristine/new tanks without natural food sources.

Chinese Algae Eater (CAE)

Gyrinocheilus aymonieri

Other
25 cm Aggressive

Sold widely as a small, peaceful algae-eating juvenile, the Chinese Algae Eater (CAE) undergoes a drastic behavioral and dietary shift as it matures. Growing up to 25cm (10 inches), adults stop eating algae, become highly territorial, and are notorious for attacking slow-moving, flat-sided fish (like Angelfish, Discus, and Goldfish) to feed on their nutrient-rich slime coat. Best kept in fast-flowing river setups with robust, fast-moving tank mates.

Zebra Pleco (L046)

Hypancistrus zebra

Catfish
8.5 cm Mostly Peaceful

A highly sought-after, strikingly beautiful black-and-white striped pleco endemic to the fast-flowing Xingu River in Brazil. Unlike common plecostomus, it is primarily carnivorous (a micropredator) and will not clean algae. They are notoriously shy, slow-growing, and require highly oxygenated, warm water with vigorous flow to thrive.

Clown Pleco (L104)

Panaqolus maccus

Catfish
9 cm Mostly Peaceful

A popular, distinctly striped dwarf pleco native to Venezuela. It is a strictly wood-eating species (xylivore); real driftwood is mandatory for its survival and digestion. Because of this diet, it produces massive amounts of sawdust-like waste, requiring excellent mechanical filtration despite its small size. They are shy and predominantly nocturnal.

Siamese Algae Eater

Crossocheilus oblongus

Cyprinids
15 cm Mostly Peaceful

Famous for being one of the few freshwater fish that actively consumes Black Beard Algae (BBA). A torpedo-shaped, active bottom-to-midwater swimmer native to Southeast Asian streams. True Siamese Algae Eaters feature a distinct black horizontal stripe that extends all the way through the tail fin. As they mature, they can become lazy, preferring prepared foods over algae, and may occasionally chase other bottom dwellers.