Redfin Thresher Pleco L116
The Redfin Thresher Pleco L116 (Aphanotorulus emarginatus) is a large South American loricariid catfish known for its armored body, spotted pattern, broad fins, and reddish to orange coloration that may appear in the fins, especially on well-conditioned specimens.
This is a peaceful bottom-dwelling pleco, but its eventual adult size makes it best suited to spacious aquariums with strong filtration, good oxygenation, plenty of hiding areas, and room to move along the bottom.
Key Features
- Attractive spotted body pattern
- Reddish to orange tones may appear in the fins
- Peaceful bottom-dwelling catfish
- Large-growing pleco species
- Excellent choice for spacious South American and community aquariums
- Appreciates caves, driftwood, rocks, and shaded resting areas
- Omnivorous diet
- Best for experienced aquarists prepared for its adult size
Fish Information
- Common Name: Redfin Thresher Pleco
- L-Number: L116
- Scientific Name: Aphanotorulus emarginatus
- Other L-Numbers: L011, L035, L108
- Fish Type: Loricariid catfish / pleco
- Origin: South America
- Water Type: Freshwater
- Temperament: Generally peaceful
- Swimming Level: Bottom
- Adult Size: Up to approximately 15–16 inches
- Diet: Omnivore
- Care Level: Intermediate
Adult Size
The Redfin Thresher Pleco is not a small pleco.
Adults may reach approximately 15–16 inches, so customers should plan for the fish's mature size rather than its size at the time of purchase.
Because of its length, heavy body, and waste production, this species requires considerably more space and filtration than smaller plecos such as bristlenose or clown plecos.
Recommended Aquarium Size
For an adult specimen, we recommend a large aquarium of approximately 100 gallons or larger, with substantial bottom area.
Tank dimensions are just as important as gallon capacity. A long, wide aquarium provides more usable space than a narrow or unusually tall aquarium.
Larger systems are preferred for multiple large bottom-dwelling fish.
Recommended Water Parameters
A practical range for the Redfin Thresher Pleco is:
- Temperature: Approximately 77–84°F
- pH: Approximately 6.0–7.5
- Water Hardness: Soft to moderately hard
- Ammonia: 0 ppm
- Nitrite: 0 ppm
- Nitrate: Kept as low as practical with regular maintenance
Stable, clean water and strong oxygenation are particularly important.
Aquarium Setup
Provide an established aquarium with excellent filtration and plenty of bottom-level structure.
Recommended setup includes:
- Strong biological and mechanical filtration
- Good surface agitation and oxygenation
- Driftwood
- Smooth rocks
- Caves and shaded hiding areas
- Open bottom space for movement
- Sand or smooth gravel substrate
- Regular partial water changes
- Avoid décor with sharp edges that could injure the fish's belly, fins, or barbels.
Filtration
Large plecos produce a substantial amount of waste.
Use a filter or combination of filters capable of handling a heavily stocked aquarium, and maintain strong water circulation without creating excessive turbulence in resting areas.
Canister filters, large hang-on-back filters, sumps, or combinations of filtration may all be appropriate depending on aquarium size.
Do not replace all biological media at once, as this can disrupt the aquarium's nitrogen cycle.
Diet
The Redfin Thresher Pleco is an omnivore and should receive a varied diet rather than being expected to survive on aquarium algae alone.
Suitable foods include:
- High-quality sinking pleco pellets
- Algae wafers
- Spirulina-based foods
- Sinking omnivore tablets
- Repashy-style gel foods
- Blanched zucchini
- Squash
- Green beans
- Other aquarium-safe vegetables
- Frozen foods as occasional supplemental protein
Feed after the aquarium lights begin to dim if the fish is reluctant to come out during the day.
Remove uneaten vegetables before they begin to deteriorate.
Does It Eat Algae?
This species may graze on algae and biofilm, but it should not be purchased solely as an algae-control fish.
Large plecos require regular prepared foods and vegetable matter even when visible algae is available in the aquarium.
No pleco should be expected to replace routine aquarium maintenance.
Driftwood
Driftwood is highly recommended.
It provides:
- Natural hiding areas
- Surfaces for biofilm growth
- Security during daylight hours
- Additional structure within the aquarium
While this pleco may graze on wood surfaces, driftwood should not be considered its sole source of nutrition.
Temperament
Redfin Thresher Plecos are generally peaceful toward fish that occupy the middle and upper levels of the aquarium.
They may become territorial with:
- Other large plecos
- Similar bottom-dwelling catfish
- Fish competing for the same cave
- Other large loricariids in limited space
Providing multiple caves and plenty of bottom area can help reduce territorial disputes.
Compatible Tankmates
Possible tankmates include:
- Larger tetras
- Rainbowfish
- Peaceful cichlids
- Angelfish
- Larger rasboras
- Barbs
- Gouramis
- Other peaceful medium to large community fish
Tankmates should be large enough that they are not easily disturbed and should tolerate similar warm freshwater conditions.
Exercise caution when combining multiple large plecos in smaller aquariums.
Plants
Redfin Thresher Plecos can be kept in planted aquariums, but mature specimens may accidentally uproot delicate plants while moving around the bottom.
Choose:
- Well-established rooted plants
- Plants attached to driftwood or rocks
- Anubias
- Java fern
- Other sturdy species
Leave ample open floor space.
Lighting and Hiding Areas
This pleco may spend much of the daytime resting under driftwood or inside a cave.
Provide multiple shaded locations so the fish feels secure.
Fish that have adequate hiding places often become more comfortable and may eventually become more visible during feeding.
Acclimation
- Turn aquarium lights off before introducing the fish.
- Float the unopened bag for approximately 15–20 minutes to equalize temperature.
- Gradually introduce small amounts of aquarium water into the bag or acclimation container.
- Carefully net or transfer the fish into the aquarium.
- Avoid adding shipping water to the display aquarium when practical.
- Leave the lights off for several hours while the fish settles.
Quarantine new fish whenever a suitable quarantine aquarium is available.
Routine Maintenance
Because this species can become large and produce substantial waste:
- Test ammonia, nitrite, nitrate, and pH regularly.
- Perform regular partial water changes.
- Vacuum accumulated waste from the substrate.
- Maintain good oxygenation.
- Clean mechanical filtration as needed.
- Preserve biological filter media during maintenance.
- Avoid sudden changes in temperature or water chemistry.
Important Care Notes
- This is a large-growing pleco.
- Do not purchase it for a small aquarium.
- Do not rely on algae as its only food source.
- Provide sinking foods and vegetable matter regularly.
- Maintain excellent filtration and oxygenation.
- Provide caves and shaded resting areas.
- Plan for the fish's adult size before purchasing.
- Never release aquarium fish into local waterways.
Frequently Asked Questions
How large does the Redfin Thresher Pleco get?
Adults may reach approximately 15–16 inches, making this a large pleco that requires substantial aquarium space.
Is L116 the only L-number for this fish?
No. This species has also been associated with L011, L035, and L108 in the aquarium trade.
Is it peaceful?
Generally yes toward midwater community fish, although large plecos may become territorial with other bottom-dwelling fish or plecos competing for caves.
Will it clean my aquarium?
It may graze on algae and biofilm, but it is not a substitute for aquarium maintenance and must be provided with a complete diet.
Does it need driftwood?
Driftwood is strongly recommended because it provides shelter, grazing surfaces, and a more natural environment.
Can I keep it with other plecos?
Possibly, but multiple large plecos require substantial bottom space, multiple hiding areas, and strong filtration.
Is it suitable for a 20- or 40-gallon aquarium?
Not long term. Its potential adult size and waste production require a much larger aquarium.
Available at Tropical Treasures Wyo
Redfin Thresher Pleco L116 are available at Tropical Treasures Wyo in Cheyenne, Wyoming, when in stock.
Live fish are available for in-store purchase or local pickup only and are not available for shipping.
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