L034 Medusa Pleco - (Ancistrus ranunculus)

Fish Details, Description and Information Below:

🐟 L034 Medusa Pleco – (Ancistrus ranunculus) – Wild-Caught Broad-Headed Brazilian Pleco

The L034 Medusa Pleco (Ancistrus ranunculus) is one of the most unusual members of the genus Ancistrus, instantly recognizable by its extremely broad, flattened head, dark coloration, and thick tentacle-like facial growths.

The dramatic facial tentacles are responsible for the name:

Medusa Pleco

because mature specimens—especially males—can develop a crown of thick projections around the snout that resembles the snakes associated with Medusa in Greek mythology.

Unlike the familiar Common Bristlenose Pleco, Ancistrus ranunculus has a remarkably wide, low-profile body adapted to sheltering inside narrow cracks, spaces between submerged rocks, and beneath flat stones.

Its unusual body shape can almost resemble a:

Tadpole or Small Aquatic Frog

when viewed from above.

The species is native to Brazil's Rio Xingu and Rio Tocantins basins, where it inhabits clear, moving freshwater over rocky bottoms.

Although many Ancistrus species are strongly plant-oriented grazers, the L034 is somewhat unusual because it readily accepts and often prefers a greater proportion of animal and insect-based foods. It should therefore be maintained as a varied omnivore rather than being purchased simply as an algae-eating fish.

This listing is for:

WILD-CAUGHT L034 MEDUSA PLECOS

🔎 Quick Facts – L034 Medusa Pleco

📛 Common Name: Medusa Pleco
📛 Other Name: Tadpole Bristlenose Catfish
🔢 L-Number: L034
🔬 Scientific Name: Ancistrus ranunculus
🐟 Family: Loricariidae
🧬 Subfamily: Hypostominae
🌿 Stock: Wild Caught
🇧🇷 Country: Brazil
🌊 Native Range: Rio Xingu and Rio Tocantins basins
📍 Type Locality: Rio Xingu near Arroz Cru, Pará, Brazil
💧 Water Type: Freshwater
📏 Typical Aquarium Adult: Approximately 5–6 inches
📏 Scientific Maximum: Approximately 19.5 cm / 7.7 inches total length
🏠 Recommended Aquarium: 40 gallons or larger for one adult
👥 Groups / Multiple Plecos: 55–75+ gallons with abundant territories
🌡️ Temperature: Approximately 79–84°F
💧 pH: Approximately 6.0–7.5
💦 Hardness: Soft to moderately mineralized
💨 Oxygenation: High
🌊 Water Movement: Moderate with strong oxygenation
🍽️ Diet: Omnivore with a stronger protein preference than many Ancistrus
😌 Temperament: Generally peaceful toward other fish; territorial around shelters
🌙 Activity: Primarily nocturnal / crepuscular
🐠 Swimming Area: Bottom
🥚 Breeding: Shelter / cave spawner with male parental care
⭐ Care Level: Intermediate
🌎 Conservation Status: Near Threatened
🏆 Type: Distinctive Brazilian L-Number Pleco

🧬 A Formally Described Species

Unlike many L-number plecos that are still awaiting formal scientific description, L034 already has a valid scientific name:

Ancistrus ranunculus

The species was formally described in:

1994

by:

Sonia Fisch-Muller
Lúcia H. Rapp Py-Daniel
Jansen Zuanon

The correct current product identification is therefore:

**L034 Medusa Pleco – (Ancistrus ranunculus)**

🐸 What Does “ranunculus” Mean?

The unusual species name:

ranunculus

is derived from Latin terminology associated with a:

Small Frog / Tadpole-Like Form

and refers to the extremely broad, flattened body and head.

When viewed from above, the L034 looks noticeably different from the more streamlined shape of an ordinary bristlenose pleco.

🐍 Why Is It Called the Medusa Pleco?

The common name comes from the fish's extraordinary facial tentacles.

Mature specimens develop thick fleshy projections around the:

Snout
Forehead
Upper head

Males can develop especially dramatic tentacles that resemble:

A Crown of Spines or Snakes

giving rise to the name:

Medusa Pleco

👃 Unusual Tentacles

The facial tentacles of Ancistrus ranunculus are different from those of many common bristlenose plecos.

They tend to be:

Thick
Heavy
Thorn-like
Relatively unbranched

rather than forming extremely fine branching structures.

This is one of the characteristics that gives mature L034s such a distinctive appearance.

♀️ Females Have Tentacles Too

One unusual characteristic of the Medusa Pleco is that:

Both Males and Females Can Develop Facial Tentacles

This can make sexing somewhat more confusing than with common captive-bred bristlenose plecos.

Mature Males Typically Develop:

Longer tentacles
Thicker tentacles
More extensive tentacle growth
Tentacles extending farther across the head

Females Typically Have:

Shorter tentacles
Less extensive tentacle development
More limited growth around the snout margin

Young specimens may remain difficult to sex.

⚫ Appearance

Adult L034 Medusa Plecos are typically very dark.

Normal coloration may include:

Deep brown
Charcoal
Gray-black
Blue-black
Nearly solid black

Some individuals may show:

Pale blotches
Gray markings
Temporary mottling

especially during:

Stress
Shipping
Acclimation
Changes in mood

👶 Juveniles May Have Spots

Young Ancistrus ranunculus can display:

Pale or White Spots

that may make them resemble the closely related-looking:

L255 Spotted Medusa Pleco

However, the spotting on typical L034:

Usually Fades or Disappears With Maturity

while L255-type fish generally retain obvious white spotting as adults.

This is an important identification point.

🆚 L034 vs. L255 Spotted Medusa Pleco

L034 and L255 are extremely similar.

Both have the characteristic:

Very broad head
Flattened body
Large sucker mouth
Thick facial tentacles

However:

L034 – Ancistrus ranunculus

Typically becomes:

Mostly Solid Dark / Black as an Adult

Juvenile spots usually fade substantially with age.

L255 – Spotted Medusa Pleco

Typically retains:

Distinct White Spots Into Adulthood

The exact taxonomic relationship between these forms has historically been debated, and L255 remains closely associated with the ranunculus group.

For accurate aquarium records:

Keep L034 and L255 Identification Separate Unless Lineage Is Known.

🌎 Native Distribution

Ancistrus ranunculus is native to:

Brazil

and occurs in the:

Rio Xingu Basin
Rio Tocantins Basin

This is more specific than simply stating:

“Amazon Basin”

The Xingu and Tocantins systems contain many highly specialized loricariid catfish adapted to rocky, oxygen-rich river environments.

🪨 Natural Habitat

Wild L034s inhabit:

Clear Running Freshwater

and are strongly associated with rocky bottom structure.

They shelter in:

Narrow rock cracks
Spaces between overlapping stones
Areas beneath flat rocks
Small rocky passages
Protected crevices

During the dry season, specimens have been collected at depths down to approximately:

3 meters / 10 feet

🌊 Current – Moderate, Not an Extreme Torrent Everywhere

The species benefits from moving water, but its scientific habitat description does not require an aquarium that is violently turbulent everywhere.

A good setup should provide:

Moderate Current + Very Good Oxygenation

with both:

Moving-Water Areas

for:

Oxygen
Natural behavior
Feeding

and:

Protected Areas

beneath rocks and inside shelters where the fish can rest.

🪨 Extremely Flat Body Shape

The Medusa Pleco's unusual flat body is not just decorative.

It is an adaptation that allows the fish to squeeze into:

Extremely Narrow Rocky Crevices

where larger predators and competitors may have difficulty reaching it.

This means aquarium shelters should include:

Low caves
Flat rock overhangs
Slate gaps
Narrow protected spaces

rather than only tall traditional pleco caves.

🏠 Aquarium Setup

Recommended features include:

Smooth rocks
Flat slate
Rock piles
Narrow crevices
Driftwood
Sand or smooth gravel
Shaded areas
Open feeding surfaces
Strong filtration
Good water movement
High dissolved oxygen

Create several protected spaces where the fish can completely disappear from view.

⚠️ Secure the Rocks

Because the fish likes very narrow areas:

Rock structures must be secure.

Never create loose rock piles that can:

Shift
Collapse
Trap the pleco

if the fish digs or wedges itself underneath them.

Flat stones can be extremely useful when arranged safely.

🏠 Caves & Flat Shelters

Traditional ceramic pleco caves can be used, but the species may also prefer:

Low slate caves
Flat ceramic shelters
Narrow rock crevices
Spaces beneath smooth stones
Flat pieces of wood

Providing multiple styles lets the fish choose its preferred shelter.

📏 Adult Size

Many aquarium references place the typical adult L034 around:

5–6 Inches

However, current FishBase records include a maximum of:

19.5 cm / Approximately 7.7 Inches Total Length

For responsible customer planning:

Expect approximately 5–6 inches normally, but allow for individuals approaching 7–8 inches.

Do not build permanent housing around an absolute 5-inch maximum.

🏠 Aquarium Size

For one adult:

40 gallons or larger

is a good long-term recommendation.

For:

Multiple L034s
Other plecos
Additional bottom dwellers

I recommend:

55–75+ gallons

depending on stocking.

Bottom area and shelter availability are more important than tank height alone.

📐 Bottom Territory Matters

Plecos spend most of their lives near the bottom.

A long aquarium provides more usable territory for:

Rock shelters
Feeding areas
Visual barriers
Separate territories

than a tall narrow aquarium of the same volume.

💨 High Oxygenation

The L034 benefits from:

Clean, Oxygen-Rich Water

Recommended methods include:

Strong surface agitation
Powerful filter returns
Air stones
Powerheads
Sump filtration
Additional circulation

This becomes especially important when keeping the fish near:

82–84°F

because warm water naturally contains less dissolved oxygen.

🌡️ Temperature

Specialist references generally place this species in warm tropical conditions.

A practical long-term range is:

79–84°F

Some experienced keepers maintain L034 at approximately:

79–86°F

but there is usually no need to run the aquarium at the extreme upper end continuously.

Stable conditions and excellent oxygenation are more important than simply increasing temperature.

💧 Water Parameters

Recommended aquarium conditions:

🌡️ Temperature: 79–84°F
💧 pH: Approximately 6.0–7.5
💦 Hardness: Soft to moderately mineralized
💨 Oxygenation: High
🌊 Flow: Moderate
☠️ Ammonia: 0 ppm
☠️ Nitrite: 0 ppm
🔄 Nitrate: Keep as low as reasonably practical

Avoid sudden changes in:

Temperature
pH
Hardness
Conductivity

especially with newly imported wild fish.

💩 Filtration

A well-established aquarium with strong biological filtration is recommended.

Suitable filtration may include:

Canister filters
Sump filtration
Hang-on-back filtration
Sponge filtration as supplemental filtration
Powerheads for circulation

Regular partial water changes help maintain:

High oxygen
Low nitrate
Stable water chemistry

🍽️ Diet – Different From the Typical Bristlenose

One of the most important husbandry points for L034 is diet.

Most Ancistrus are heavily oriented toward:

Plant matter
Algae
Biofilm
Vegetable foods

However:

Ancistrus ranunculus Shows a Stronger Preference for Protein-Rich Foods

than many familiar bristlenose plecos.

The safest description is:

Omnivore With a Stronger Animal-Protein Component Than Typical Ancistrus

🦐 Recommended Protein Foods

Suitable foods include:

Mysis shrimp
Brine shrimp
Bloodworms
Insect larvae
Chopped shrimp
Krill
Insect-based sinking pellets
High-quality omnivore pellets
Sinking catfish tablets

These foods should form a meaningful part of the diet.

🌿 Plant-Based Foods Still Matter

Protein preference does not mean the fish should be maintained exclusively on meat.

Also provide:

Algae wafers
Spirulina foods
Zucchini
Squash
Green beans
Vegetable-containing pellets
Quality gel foods

The goal is:

A Balanced Omnivorous Diet

🚫 Not Simply an Algae Cleaner

L034 should not be purchased merely to clean algae from an aquarium.

Although it may graze:

Algae
Biofilm
Organic material

it requires intentional feeding.

Aquarium algae alone will not provide complete nutrition.

🪵 Driftwood

Driftwood is useful because it provides:

Cover
Shade
Biofilm
Territory boundaries
Natural-looking structure

However:

L034 is not a specialized wood-eating pleco.

Wood should be considered:

Habitat and Enrichment

rather than its main nutritional requirement.

🌙 Nocturnal Behavior

The Medusa Pleco is primarily:

Nocturnal / Crepuscular

New wild-caught specimens may remain hidden for much of the day.

Activity usually increases:

At dusk
After lights go out
During feeding
Under subdued lighting

Established specimens may eventually become more visible during daytime feeding.

🧪 Wild-Caught Acclimation

Because this listing is for:

WILD-CAUGHT L034 MEDUSA PLECOS

careful acclimation is particularly important.

After arrival:

Maintain strong oxygenation
Keep lighting subdued
Provide immediate hiding areas
Avoid aggressive tankmates
Monitor feeding carefully
Watch body condition
Keep water exceptionally clean

Wild plecos can take time to accept unfamiliar aquarium foods.

🍽️ Make Sure the Fish Is Actually Eating

In community aquariums, more aggressive fish can consume food before a shy pleco emerges.

Feed some food:

Near the L034's shelter
At dusk
After lights out

Monitor the abdomen for:

Severe hollowing
Sunken belly
Loss of body mass

These can indicate inadequate food intake or health problems.

😌 Temperament

Toward most midwater fish, L034 is generally:

Peaceful

Suitable companions may include appropriately sized fish that tolerate:

Warm water
Good current
High oxygen

However, adult plecos can become territorial around preferred shelters.

⚠️ Territorial Behavior

Conflict may occur between:

Two mature males
Other Ancistrus
Similar plecos
Bottom dwellers using the same shelters

Disputes can involve:

Chasing
Pushing
Blocking shelter entrances
Odontode contact

Provide:

More Shelters Than Plecos

whenever possible.

🐠 Tankmates

Possible tankmates include appropriately selected:

Tetras
Pencilfish
Larger characins
Geophagus
Peaceful cichlids
Other compatible catfish

Avoid fish that:

Require cool water
Constantly attack bottom dwellers
Prevent the pleco from feeding
Occupy every available cave

♂️ Male vs. Female

Sexing mature L034s is easier than sexing juveniles.

Mature Males

Typically develop:

Much heavier facial tentacles
Longer tentacles
More extensive tentacle coverage
Greater territorial behavior

Mature Females

May still develop:

Facial tentacles

but they are usually:

Shorter
Less numerous
Concentrated closer to the snout edge

This is important because female L034s can appear more “male-like” than females of some familiar bristlenose species.

🥚 Breeding

Captive breeding of Ancistrus ranunculus has been successfully documented.

Like other Ancistrus, the species uses a protected spawning shelter where:

The Male Provides Parental Care

The female deposits eggs inside or beneath the protected spawning area.

The male then:

Guards the eggs
Fans them
Protects the developing embryos
Remains with the brood

🪨 An Interesting Documented Spawn

Recent captive breeding work has shown that L034 does not always insist on a conventional ceramic pleco cave.

A documented successful spawning occurred:

Under a Flat Porcelain Tile

The eggs were attached to the underside or “ceiling” of the protected shelter.

The male remained beneath the structure while caring for the eggs.

This fits the species' natural preference for:

Flat rocks
Narrow cracks
Low shelters

🏠 Breeding Shelter

When attempting breeding, offer several choices:

Low ceramic caves
Slate caves
Flat tile shelters
Narrow rock crevices
One-ended pleco caves

The fish may prefer:

A Low, Tight, Horizontal Shelter

rather than a large open cave.

💨 Breeding Conditions

Potential breeding conditions should emphasize:

Mature healthy adults
Excellent oxygenation
Soft to moderately mineralized water
Clean water
Warm temperature
Large water changes
Multiple spawning shelters
Heavy conditioning with varied foods

L034 is more demanding to breed than ordinary commercially produced bristlenose plecos.

👶 Fry

After the eggs hatch, young fish initially rely on their:

Yolk Sacs

Once feeding independently, foods may include:

Fine sinking omnivore foods
Crushed pleco pellets
Baby brine shrimp
Fine insect-based foods
Spirulina-containing foods
Quality gel foods

Maintain extremely clean water and avoid leaving uneaten food to decay.

🌎 Conservation Status

Ancistrus ranunculus is currently assessed as:

Near Threatened

Its natural distribution is restricted to portions of Brazil's:

Rio Xingu
Rio Tocantins

Responsible keeping is especially important with wild-caught specimens.

Never purchase this fish without being prepared to provide appropriate permanent housing.

⭐ Why Keep an L034 Medusa Pleco?

The L034 is one of the most distinctive Ancistrus species available because of its combination of:

🐍 Dramatic Medusa-like facial tentacles
⚫ Deep dark coloration
🐸 Extremely broad tadpole-shaped head
🪨 Specialized rock-crevice behavior
🌊 Brazilian river origin
🦐 Unusual protein preference
🥚 Interesting paternal breeding behavior
🌙 Nocturnal personality
🏆 Strong L-number collector appeal

A mature male displaying a full crown of thick facial tentacles looks dramatically different from an ordinary bristlenose pleco.

⚠️ Important Considerations

Before purchasing an L034 Medusa Pleco:

The correct scientific name is Ancistrus ranunculus.
L034 is a formally described species.
It occurs in Brazil's Xingu and Tocantins river basins.
Do not list its origin simply as “Amazon Basin.”
This listing is for wild-caught fish.
Typical aquarium adults are often around 5–6 inches.
Scientific records reach approximately 7.7 inches total length.
Provide approximately 40 gallons or larger.
Use larger aquariums for groups or multiple bottom dwellers.
Provide narrow rocky crevices and flat shelters.
Maintain high dissolved oxygen.
Provide moderate water movement.
Maintain warm, clean water.
Keep ammonia and nitrite at zero.
Feed a varied omnivorous diet.
Provide more animal/insect protein than you would for a typical Common Bristlenose.
Still include vegetable and algae-based foods.
Do not rely solely on aquarium algae.
Understand that juvenile spotting may disappear with maturity.
Do not automatically confuse L034 with L255.
Expect some territorial behavior around shelters.
Preserve L-number and locality information when breeding.
Never release aquarium fish into natural waterways.

🧬 Taxonomy

The currently accepted scientific name is:

Ancistrus ranunculus Muller, Rapp Py-Daniel & Zuanon, 1994

Classification:

Order: Siluriformes
Family: Loricariidae
Subfamily: Hypostominae
Genus: Ancistrus
Species: ranunculus

For this product, use:

**L034 Medusa Pleco – (Ancistrus ranunculus)**

🆚 L255 Identification Disclaimer

The L255 Spotted Medusa Pleco is extremely similar to Ancistrus ranunculus.

Typical L034 juveniles may have pale spotting but generally become much more uniformly dark as they mature.

L255-type fish typically retain their:

White Spotted Pattern

into adulthood.

Because the exact relationship between these closely related forms has been debated, preserve the fish's original:

L-number
Collection information
Supplier identification

whenever possible.

Do not intentionally mix identified L034 and L255 breeding lines and later sell the offspring as pure locality fish.

🚚 Live Fish Shipping

Live fish are professionally packed for safe transport.

Shipping availability depends on:

Fish size
Destination
Weather conditions
Carrier availability
Applicable state and local regulations

Please review our Shipping & Payment Information and Live Arrival Guarantee / DOA Policy before ordering.

⚠️ Buyer Responsibility

Customers are responsible for confirming that Ancistrus ranunculus may legally be purchased, possessed, transported, and received in their state or local jurisdiction before ordering.

Never release aquarium fish into natural waterways.

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L034 Medusa Pleco – Ancistrus ranunculus

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Wild-caught L034 Medusa Pleco (Ancistrus ranunculus) for sale online. Distinctive Brazilian bristlenose with a broad flattened head and dramatic facial tentacles. Learn about adult size, diet, tank requirements, breeding and care.