Bristlenose Pleco (Ancistrus cirrhosus)

Bristlenose Plecos are nocturnal by nature and hiding during daylight hours is completely normal behavior, not a sign of illness. They are crepuscular and nocturnal, meaning they are most active at dawn and dusk and feed primarily at night. During the day, they retreat to caves, driftwood crevices, or plant thickets to rest. This is an anti-predator adaptation from their native Amazon tributaries.

If your pleco is not eating at all, even at night, investigate the following:

• Insufficient Hiding Places: A pleco without a secure cave will remain stressed and refuse food. Provide at least one cave per fish plus driftwood with crevices.
• Competition for Food: Fast-swimming tank mates such as Tetras or Barbs may consume all food before it reaches the bottom. Target-feed your pleco directly at the cave entrance after turning off the aquarium lights.
• Wrong Food: Bristlenose Plecos cannot survive on algae alone. If you are not offering sinking wafers or blanched vegetables, the fish may be starving despite a clean tank.
• Water Quality: Any detectable ammonia or nitrite suppresses appetite immediately. Test parameters and perform water changes.
• Temperature Too Low: Temperatures below 70 degrees Fahrenheit (21 degrees Celsius) slow metabolism and reduce feeding.

Pro tip: Place a slice of blanched zucchini or cucumber in the tank just before bed and check it in the morning. If bite marks are present, your pleco is eating normally and simply being nocturnal.

Yes. Bristlenose Plecos are fully compatible with Corydoras catfish, Otocinclus, Kuhli Loaches, and other peaceful bottom-dwelling species. They are not aggressive and do not compete for territory with non-pleco bottom dwellers. However, you must ensure sufficient space and food for all bottom-dwelling inhabitants. In a 20-gallon tank, one Bristlenose Pleco plus a small group of 4-6 Corydoras is the maximum bottom-dwelling biomass recommended.

Feeding strategy: Bristlenose Plecos are primarily herbivores, while Corydoras are omnivores. Offer sinking algae wafers and vegetables for the pleco, and sinking omnivore pellets for the Corydoras. Place food at opposite ends of the tank to reduce competition. Corydoras are active, social fish that will not intimidate the slower, more reclusive pleco.

Avoid housing Bristlenose Plecos with other pleco species, particularly other Ancistrus males or larger plecos such as Common Plecos (Pterygoplichthys pardalis), which grow to 18-20 inches (45-50 cm) and will outcompete or bully the much smaller Bristlenose. Also avoid aggressive bottom dwellers such as Red Tail Sharks or Rainbow Sharks, which may harass plecos.

Yes. Driftwood is absolutely mandatory for Bristlenose Plecos, not merely decorative. In the wild, they consume significant quantities of lignin and cellulose from submerged wood, which aids digestion and provides essential nutrients that cannot be obtained from prepared foods alone. A tank without driftwood will result in malnourished plecos, stunted growth, and shortened lifespan.

Provide at least one piece of driftwood per 10 gallons (38 liters). Mopani wood, Malaysian driftwood, and cholla wood are all excellent choices. The wood should have crevices and rough surfaces where algae and biofilm can colonize, providing natural grazing opportunities. Bristlenose Plecos will rasp directly on the wood, consuming the outer layers. Over time, you may notice characteristic rasp marks on the driftwood surface.

Driftwood also serves as a hiding place and territory marker. Males often establish their breeding caves adjacent to or beneath a piece of driftwood. If you do not provide driftwood, your pleco may attempt to rasp on aquarium silicone, plastic decor, or plant leaves, none of which provide nutritional benefit.

Note: Driftwood will leach tannins into the water, slightly lowering pH and creating a tea-colored tint. This is beneficial for Bristlenose Plecos and most South American community fish. If you prefer crystal-clear water, use activated carbon in your filter, but do not remove the driftwood itself.

Through decades of selective breeding, numerous distinct color and fin varieties of Bristlenose Pleco have been developed. All varieties share identical care requirements and reach the same adult size of 4-5 inches (10-12.7 cm):

• Common / Wild Type: Brown, green, or gray body with white or yellow spots scattered across the bony plates. Lighter abdomen and darker back. The original form found in the Amazon basin.
• Albino: Pale yellowish to cream-white body with red eyes. Spots are faint or absent. One of the most commonly available varieties.
• Calico / Piebald: Mottled pattern of brown, orange, and white patches across the body. Each individual has a unique pattern.
• Super Red / Red: Vibrant reddish-orange body coloration. Highly sought after and commands a premium price.
• Chocolate / Brown: Uniform dark brown body with minimal spotting. Sometimes called the Chocolate Bristlenose.
• Starlight / White Seam: Dark body with white spots and a distinctive white edge along the dorsal and caudal fins.
• Longfin: Elongated, flowing fins that trail behind the body. Available in common, albino, and super red color forms. Requires avoidance of fin-nipping tank mates.
• Green Dragon: Dark greenish body with intricate spotted patterning. Often bred in longfin form.

When selecting any variety, avoid individuals with sunken bellies, clamped fins, or damaged barbels, as these indicate poor health or inadequate nutrition.