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Species profile

L043 Bristlenose Plecostomus

Ancistrus sp. (L043)

Common names: L043 Bristlenose Plecostomus, L043, Bristlenose Plecostomus

Undescribed speciesPlecostomus
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Countries of origin

  • See all stock from French Guiana

Good fit for your tank?

Good fit for

  • A peaceful community with wood and several caves
  • A keeper wanting clear adult sexual dimorphism
  • A breeder able to keep the L043 line separate

Think carefully if

  • Different Ancistrus forms will be allowed to cross
  • There are too few caves for multiple males
  • You expect algae alone to provide a complete diet

L043 Bristlenose Plecostomus is a South American loricariid currently filed as Ancistrus sp. (L043). A dependable species-specific maximum adult size is not available, so the aquarium recommendation is deliberately conservative. It requires stable, oxygen-rich water, suitable caves, and deliberate feeding.

Appearance and Identification

A coded bristlenose pleco with a dark body and pale spotting or mottling. Mature males develop the soft facial tentacles characteristic of Ancistrus, while exact pattern can vary with collection.

This profile is identified by L043 and the current assignment Ancistrus sp. (L043). Do not merge it with a visually similar L-number without matching collection locality and diagnostic features. The L-number remains the primary stable identifier because the form has not been formally described.

Mature males develop prominent tentacles across the snout and often a broader head. Females have few or no central snout tentacles and become fuller through the abdomen.

Tank Requirements

Suggested filter
About 300–380 litres an hour
Suggested heater
About 75–125 W for this tank
Minimum tank volume
75 litres
Minimum tank length
60 cm
Minimum group size
1
Recommended group size
2
Activity level
Moderate
Flow preference
Moderate
Planting preference
Moderately planted
Hiding places
Yes
Lid recommended
Yes
Jumping risk
Low

Provide driftwood, shaded cover, several tight caves and strong filtration. A group needs enough separated shelters to prevent dominant males from controlling every cave.

Behaviour and Tankmates

Generally peaceful with community fish but territorial around caves. Adult males may fight or trap one another in cramped shelter arrangements.

Can be kept singly, as a pair, or in a managed group when each adult has a separate shelter and feeding area.

Mature males defend breeding caves, but conflict is usually manageable with sufficient floor space and shelter.

Suitable for peaceful communities if each pleco has its own retreat and feeding area. Avoid crossing it with other Ancistrus if preserving the L043 line matters.

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Water Parameters

Temperature
23–29 °C
pH
5.5–7.8
GH
2–15
KH
0–8
TDS
40–280
Stability importance
Important

Maintain stable, clean, oxygen-rich freshwater. Strong filtration and gas exchange are essential because warm water, protein-rich feeding, and loricariid waste can reduce oxygen and impair water quality.

Parameter caveat
Acclimate slowly to changes in temperature and conductivity. Keep ammonia and nitrite at zero, control nitrate, and never allow caves or rockwork to create stagnant waste pockets.

Feeding

Diet types
Algae Grazer, Aufwuchs Grazer, Herbivore, Omnivore
Feeding frequency
Daily
Preferred foods
  • Complete bristlenose or herbivore waferUse a sinking food rich in plant matter, algae, and fibre.
  • Blanched courgette, squash, or green beanOffer varied vegetables and remove them before they deteriorate.
  • Natural aufwuchs and soft algaeMaintain mature grazing surfaces while still providing a complete diet.
  • Occasional frozen insect larvae or brine shrimpUse modest portions as supplementary protein.

Offer vegetable-rich sinking foods, soft vegetables, algae and biofilm, with occasional protein. It needs deliberate feeding even when algae is present.

Feed after lights dim and place food near every occupied cave. Confirm that subordinate fish eat, and remove rich leftovers before they affect water quality.

Breeding

Breeding type
Cave Spawner, Egg Layer
Breeding difficulty
Difficult
Breeding temperature
26 °C
Breeding pH
6.8
Incubation
6 days
Parental care
Paternal care
Baby foods
  • Mature biofilmContinuous grazing supports fry between targeted feeds.
  • Finely powdered sinking foodFeed tiny portions close to the breeding cave several times daily.
  • Newly hatched brine shrimpUseful supplementary protein once fry leave the cave and can take moving prey.

Ancistrus are male-guarded cave spawners and L043 may breed readily once mature. The male guards the clutch, while fry require clean water, biofilm and suitable vegetable foods.

Habitat and Origin

Geographic origin
Amazon Basin, French Guiana, South America
Natural habitat
Fast-Flowing Stream, Freshwater River, Freshwater Stream, Rocky Shoreline
Aquarium contexts
Breeding Tank, Freshwater Aquarium, Freshwater Community, Planted Aquarium, Species-Only Aquarium
Audience level
Intermediate

Classification

Profile type
Undescribed species
Genus
Ancistrus
Family
Loricariidae
Species group
Fish, Plecostomus

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L053 Harttia Plecostomus

Harttia sp. (L053)

Care level
Advanced
Minimum tank
120 litres
Temperature
20–27 °C

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