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Species profile

Isaac’s Plecostomus L274

Baryancistrus isaaci

Common names: Isaac's Plecostomus L274, L274

Recognized speciesPlecostomus
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Adult size

Up to 18 cm

Typical adult length 13.5–18 cm.

Up to 18 cm

Countries of origin

  • See all stock from Brazil

Good fit for your tank?

Good fit for

  • An experienced keeper with a mature warm pleco aquarium
  • A cave-rich setup with strong oxygenation
  • An aquarist able to monitor shy feeders

Think carefully if

  • The aquarium is new or lightly filtered
  • Food competition cannot be controlled
  • You expect straightforward breeding

Isaac’s Plecostomus L274 is a South American loricariid represented by L274. It requires stable oxygen-rich water, suitable caves, and deliberate species-appropriate feeding.

Appearance and Identification

A dark Baryancistrus patterned with contrasting pale to yellow spots over the head, body and fins. The exact spot size and fin contrast can change as the fish grows.

Use the L-number identification L274 together with the current assignment Baryancistrus isaaci. Do not merge it with visually similar forms without matching collection locality and diagnostic features.

Mature males generally develop a broader head and stronger odontodes along the cheeks and pectoral region. Females are fuller-bodied, while juveniles are difficult to sex.

Tank Requirements

Suggested filter
About 1,000–1,250 litres an hour
Suggested heater
About 250–375 W for this tank
Minimum tank volume
250 litres
Minimum tank length
120 cm
Minimum group size
1
Recommended group size
3
Activity level
Moderate
Flow preference
High
Planting preference
Lightly planted
Hiding places
Yes
Lid recommended
Yes
Jumping risk
Low

Use warm, highly oxygenated water with strong filtration, rock and wood grazing surfaces and individual caves. Newly imported fish should be monitored closely for weight loss.

Behaviour and Tankmates

Usually shy but territorial around caves and food. Adults may become forceful with similar plecos if the aquarium lacks separated territories.

Can be kept singly. A pair or group requires several appropriately sized caves and enough floor area for every adult to feed without being trapped.

Mature males commonly defend caves and favoured feeding areas from similarly shaped loricariids.

Peaceful midwater fish are suitable. Other loricariids require ample floor space, separate shelters and direct feeding access.

Check tankmates for this species

Water Parameters

Temperature
26–31 °C
pH
5.5–7.5
GH
1–15
KH
0–6
TDS
30–240
Stability importance
Critical

Maintain stable clean water with strong oxygenation. Warm water, protein-rich food, wood waste, and crowded hardscape can rapidly reduce oxygen and degrade water quality.

Parameter caveat
Acclimate slowly to temperature and conductivity changes. Keep ammonia and nitrite at zero, control nitrate, and inspect caves and rockwork for trapped waste.

Feeding

Diet types
Aufwuchs Grazer, Herbivore, Omnivore
Feeding frequency
Daily
Preferred foods
  • Natural aufwuchs and biofilmMaintain mature rocks and wood for continuous supplementary grazing.
  • Complete herbivore or algae waferUse a high-quality sinking staple with fibre.
  • Blanched leafy greens or courgetteOffer occasionally and remove leftovers.
  • Frozen daphnia or insect larvaeUse small portions as supplementary protein.

Offer vegetable and algae-rich sinking foods, soft vegetables and biofilm, with modest invertebrate protein. Natural algae is not sufficient by itself.

Feed after lights dim and distribute food near every occupied shelter. 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
28.5 °C
Breeding pH
6.5
Brood or egg count
Usually several dozen adhesive eggs, with clutch size depending on species and female size.
Incubation
7 days
Parental care
Paternal care
Baby foods
  • Mature biofilmProvides continuous grazing after fry leave the cave.
  • Fine powdered sinking foodFeed tiny portions close to shelter several times daily.
  • Newly hatched brine shrimpUse as supplementary protein once fry can take moving prey.

Specific breeding reports are limited. A male-guarded cave spawning method is expected, but the species should be treated as a demanding breeding subject.

Habitat and Origin

Geographic origin
Amazon Basin, Brazil, South America
Natural habitat
Fast-Flowing Stream, Freshwater River, Rocky Shoreline
Aquarium contexts
Freshwater Aquarium, High-Flow Aquarium, Large Freshwater Aquarium, Species-Only Aquarium
Audience level
Advanced

Classification

Profile type
Recognized species
Genus
Baryancistrus
Family
Loricariidae
Species group
Fish, Plecostomus
Previous scientific names
Baryancistrus sp. (L274), Historic L-number designation retained for identification.

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