Photo: Ernst Haeckel (Public domain) — via Wikimedia Commons
Common Pleco (Hypostomus plecostomus)
The ultimate algae-scraper — but this gentle giant grows to 45 cm and will outgrow almost every home aquarium it is sold into.
Will it live with a Common Pleco?
We compare each fish against your common pleco on temperament, size, water parameters and swimming zone. Set your tank size and filter the results.
- Bichir✅ CompatibleSemi-aggressive · 45 cm · Medium care · 24–28 °C (75–82 °F)
- Peaceful + Semi-aggressive, but with no direct clash here, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Black Ghost Knifefish✅ CompatibleSemi-aggressive · 45 cm · Hard care · 24–28 °C (75–82 °F)
- Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Cuban Cichlid✅ CompatibleAggressive · 30 cm · Hard care · 24–28 °C (75–82 °F)
- Peaceful + Aggressive, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Elephant-nose Knifefish✅ CompatiblePeaceful · 35 cm · Hard care · 24–29 °C (75–84 °F)
- Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Flowerhorn Cichlid✅ CompatibleAggressive · 30 cm · Medium care · 25–30 °C (77–86 °F)
- Peaceful + Aggressive, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Golden Sailfin Pleco✅ CompatibleSemi-aggressive · 45 cm · Medium care · 22–28 °C (72–82 °F)
- Peaceful + Semi-aggressive, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Goldfish✅ CompatiblePeaceful · 30 cm · Medium care · 18–22 °C (64–72 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Jaguar Cichlid✅ CompatibleAggressive · 55 cm · Hard care · 25–30 °C (77–86 °F)
- Peaceful + Aggressive, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Kissing Gourami✅ CompatibleSemi-aggressive · 30 cm · Medium care · 22–28 °C (72–82 °F)
- Compatible on the things that matter: shared water near 22–28 °C, workable temperaments, and no predator-and-prey size gap.
- Leopard Cactus Pleco✅ CompatibleSemi-aggressive · 30 cm · Hard care · 24–30 °C (75–86 °F)
- Peaceful + Semi-aggressive, but with no direct clash here, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Midas Cichlid✅ CompatibleAggressive · 35 cm · Hard care · 24–28 °C (75–82 °F)
- Peaceful + Aggressive, but with no direct clash here, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Oscar✅ CompatibleAggressive · 35 cm · Medium care · 23–28 °C (73–82 °F)
- Peaceful + Aggressive, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Peacock Eel✅ CompatibleSemi-aggressive · 30 cm · Medium care · 22–28 °C (72–82 °F)
- Peaceful + Semi-aggressive, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Pearlscale Cichlid✅ CompatibleAggressive · 30 cm · Medium care · 22–28 °C (72–82 °F)
- Peaceful + Aggressive, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Red Devil Cichlid✅ CompatibleAggressive · 38 cm · Medium care · 24–28 °C (75–82 °F)
- Peaceful + Aggressive, but with no direct clash here, and their water overlaps around 24–28 °C — no size, zone or temperament conflicts.
- Royal Pleco✅ CompatibleSemi-aggressive · 43 cm · Medium care · 23–28 °C (73–82 °F)
- Peaceful + Semi-aggressive, but with no direct clash here, and their water overlaps around 23–28 °C — no size, zone or temperament conflicts.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Sailfin Pleco✅ CompatiblePeaceful · 50 cm · Medium care · 22–28 °C (72–82 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Silver Cichlid✅ CompatibleSemi-aggressive · 30 cm · Medium care · 24–28 °C (75–82 °F)
- Compatible on the things that matter: shared water near 24–28 °C, workable temperaments, and no predator-and-prey size gap.
- Spotted Knifefish✅ CompatibleAggressive · 45 cm · Hard care · 22–28 °C (72–82 °F)
- Peaceful + Aggressive, but with no direct clash here; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Spotted Pleco✅ CompatibleSemi-aggressive · 30 cm · Easy care · 18–26 °C (64–79 °F)
- Compatible on the things that matter: shared water near 22–26 °C, workable temperaments, and no predator-and-prey size gap.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Texas Cichlid✅ CompatibleAggressive · 33 cm · Medium care · 20–26 °C (68–79 °F)
- Peaceful + Aggressive, but with no direct clash here, and their water overlaps around 22–26 °C — no size, zone or temperament conflicts.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- True Parrot Cichlid✅ CompatibleSemi-aggressive · 33 cm · Hard care · 23–28 °C (73–82 °F)
- Compatible on the things that matter: shared water near 23–28 °C, workable temperaments, and no predator-and-prey size gap.
- Walking Catfish✅ CompatibleAggressive · 50 cm · Medium care · 20–28 °C (68–82 °F)
- Peaceful + Aggressive, but with no direct clash here, and their water overlaps around 22–28 °C — no size, zone or temperament conflicts.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Yellow-spotted Pleco✅ CompatiblePeaceful · 35 cm · Medium care · 24–27 °C (75–81 °F)
- Both are peaceful; temperature, pH and hardness ranges all overlap and neither outsizes the other enough to be a threat.
- Both favour the bottom of the tank — offer enough cover so they aren't always in each other's space.
- Black Belt Cichlid⚠️ With cautionAggressive · 35 cm · Hard care · 24–30 °C (75–86 °F)
- Your 380 L tank is below the ~450 L this pairing really wants — crowding raises aggression.
- Black Doras Catfish⚠️ With cautionPeaceful · 60 cm · Hard care · 22–28 °C (72–82 °F)
- Your 380 L tank is below the ~500 L this pairing really wants — crowding raises aggression.
- Butter Catfish⚠️ With cautionSemi-aggressive · 45 cm · Medium care · 24–28 °C (75–82 °F)
- Your 380 L tank is below the ~680 L this pairing really wants — crowding raises aggression.
- Clown Loach⚠️ With cautionPeaceful · 30 cm · Medium care · 25–30 °C (77–86 °F)
- Your 380 L tank is below the ~400 L this pairing really wants — crowding raises aggression.
- Fahaka Puffer⚠️ With cautionAggressive · 45 cm · Hard care · 24–26 °C (75–79 °F)
- Your 380 L tank is below the ~450 L this pairing really wants — crowding raises aggression.
- Gold Zebra Catfish⚠️ With cautionAggressive · 55 cm · Hard care · 23–27 °C (73–81 °F)
- Your 380 L tank is below the ~500 L this pairing really wants — crowding raises aggression.
- Imperial Flower Loach⚠️ With cautionSemi-aggressive · 50 cm · Hard care · 15–22 °C (59–72 °F)
- Your 380 L tank is below the ~750 L this pairing really wants — crowding raises aggression.
- Lima Shovelnose Catfish⚠️ With cautionSemi-aggressive · 50 cm · Hard care · 23–30 °C (73–86 °F)
- Your 380 L tank is below the ~760 L this pairing really wants — crowding raises aggression.
- Lyre Tail Pleco⚠️ With cautionSemi-aggressive · 63 cm · Hard care · 21–27 °C (70–81 °F)
- Your 380 L tank is below the ~1500 L this pairing really wants — crowding raises aggression.
- Malawi Trout Cichlid⚠️ With cautionAggressive · 35 cm · Hard care · 24–28 °C (75–82 °F)
- Different pH ranges (6.5–7.5 vs 7.8–8.6); doable if you sit in the shared band, but not ideal long-term.
- Your 380 L tank is below the ~600 L this pairing really wants — crowding raises aggression.
- Mbu Puffer⚠️ With cautionAggressive · 67 cm · Hard care · 24–28 °C (75–82 °F)
- Your 380 L tank is below the ~757 L this pairing really wants — crowding raises aggression.
- Orinoco Sailfin Pleco⚠️ With cautionSemi-aggressive · 50 cm · Medium care · 22–28 °C (72–82 °F)
- Your 380 L tank is below the ~450 L this pairing really wants — crowding raises aggression.
- Spotted Shovelnose Catfish⚠️ With cautionSemi-aggressive · 55 cm · Hard care · 22–28 °C (72–82 °F)
- Your 380 L tank is below the ~570 L this pairing really wants — crowding raises aggression.
- Tatauaia Payara⚠️ With cautionAggressive · 59 cm · Hard care · 24–28 °C (75–82 °F)
- Your 380 L tank is below the ~2000 L this pairing really wants — crowding raises aggression.
- True Red Terror Cichlid⚠️ With cautionAggressive · 35 cm · Hard care · 22–28 °C (72–82 °F)
- Your 380 L tank is below the ~570 L this pairing really wants — crowding raises aggression.
- Yellowjacket Cichlid⚠️ With cautionAggressive · 35 cm · Hard care · 24–28 °C (75–82 °F)
- Your 380 L tank is below the ~450 L this pairing really wants — crowding raises aggression.
- Angelfish⛔ Not recommendedSemi-aggressive · 15 cm · Medium care · 24–30 °C (75–86 °F)
- Angelfish is bite-sized to a 45 cm common pleco — it will be eaten.
- Banjo Catfish⛔ Not recommendedPeaceful · 15 cm · Medium care · 20–26 °C (68–79 °F)
- Common Pleco (45 cm) is big enough to swallow the 15 cm Banjo Catfish whole.
- Blue Flash Cichlid⛔ Not recommendedSemi-aggressive · 15 cm · Medium care · 24–28 °C (75–82 °F)
- Size gap is too large (45 vs 15 cm): Common Pleco will treat Blue Flash Cichlid as food.
- Bumblebee Cichlid⛔ Not recommendedAggressive · 15 cm · Medium care · 24–28 °C (75–82 °F)
- Size gap is too large (45 vs 15 cm): Common Pleco will treat Bumblebee Cichlid as food.
- pH preferences only just meet (Common Pleco 6.5–7.5 vs Bumblebee Cichlid 7.8–8.6) — target the overlap and acclimate slowly.
- Clown Barb⛔ Not recommendedSemi-aggressive · 15 cm · Medium care · 24–30 °C (75–86 °F)
- Clown Barb is bite-sized to a 45 cm common pleco — it will be eaten.
- Keep Clown Barb in a shoal of 6+ or it gets stressed and nippy.
- Denison Barb⛔ Not recommendedPeaceful · 15 cm · Medium care · 18–25 °C (64–77 °F)
- Size gap is too large (45 vs 15 cm): Common Pleco will treat Denison Barb as food.
- Keep Denison Barb in a shoal of 6+ or it gets stressed and nippy.
- Dolphin Cichlid⛔ Not recommendedSemi-aggressive · 15 cm · Medium care · 23–28 °C (73–82 °F)
- Common Pleco (45 cm) is big enough to swallow the 15 cm Dolphin Cichlid whole.
- Eureka Red Peacock Cichlid⛔ Not recommendedSemi-aggressive · 15 cm · Medium care · 24–28 °C (75–82 °F)
- Size gap is too large (45 vs 15 cm): Common Pleco will treat Eureka Red Peacock Cichlid as food.
- Different pH ranges (6.5–7.5 vs 7.8–8.6); doable if you sit in the shared band, but not ideal long-term.
Compatibility is computed from each species' care data — a strong starting point, not a guarantee. Individual temperament varies, so always introduce new fish slowly and watch them.
Common Pleco care specs
- Care level
- Medium
- Breeding
- Very Hard
- Max size
- 45 cm (17.7 in)
- Min tank size
- 380 L (100.4 gal)
- Temperature
- 22–28 °C (72–82 °F)
- pH
- 6.5–7.5
- Hardness
- 5–25 dGH
- Lifespan
- 10–15 years
- Diet
- Omnivore
- Swim level
- Bottom
- Group size
- Best alone or in a pair
- Family
- Loricariidae
- Origin
- South America — coastal rivers of northeastern Brazil, Trinidad and Tobago; widely introduced worldwide
What is a Common Pleco?
The common pleco (Hypostomus plecostomus) is a large, armoured suckermouth catfish native to the coastal rivers of northeastern Brazil and Trinidad and Tobago. Belonging to the family Loricariidae — the largest family of catfish — it is immediately recognisable by its flattened, torpedo-shaped body, bony scutes running in rows from head to tail, and the underslung, rasping mouth that gives it its “suckermouth” nickname.
Juveniles are one of the most heavily sold fish in the aquarium trade, marketed as a living algae solution for virtually any tank. The honest version of that sales pitch is far more complicated: this species grows to 45 cm (18 in) and lives 10–15 years, producing a waste load that will overwhelm most filters and outgrow most tanks long before it reaches maturity. Hobbyists who plan for the adult, not the 5 cm (2 in) juvenile, are the ones who get to enjoy this remarkable fish for its full lifespan.
Where do Common Plecos come from?
Wild common plecos originate from the coastal river systems of northeastern Brazil and the islands of Trinidad and Tobago — fast-flowing, turbid, warm lowland rivers that run through tropical forest. The water is warm (22–28 °C / 72–82 °F), moderately soft to hard, and carries a lot of organic material — submerged wood, leaf litter and biofilm-coated rock are core features of pleco habitat.
The species has been so widely introduced around the world through the aquarium trade — particularly through irresponsible release — that feral populations now exist in Florida, Hawaii, parts of Australia and numerous other subtropical regions, where they compete aggressively with native bottom-feeders. This is a sobering reminder: never release aquarium fish into the wild.
What size tank does a Common Pleco need?
The realistic minimum for a single adult is 380 litres (100 gallons). This is not conservative padding — a fully grown pleco at 45 cm needs the physical space to turn around, and its waste output is comparable to a mid-sized cichlid. Trying to keep an adult pleco in anything smaller risks chronically poor water quality, stunted growth and shortened lifespan.
Plan the tank around the adult from the start. If you can only maintain a tank smaller than 380 L, a dwarf loricariid such as a bristlenose pleco (Ancistrus sp.) is a far more practical algae-scraper. For the common pleco, go big or plan to upgrade.
Furnish the tank with large pieces of driftwood — plecos rasp wood not just for enrichment but for essential dietary fibre and gut microbiota. Provide at least one cave or PVC pipe sized for an adult as a refuge, because plecos are nocturnal and rest hidden during the day. Heavy, efficient external canister filtration rated well above the tank volume is non-negotiable; these fish produce substantial ammonia and solid waste.
What water parameters do Common Plecos need?
- Temperature: 22–28 °C (72–82 °F)
- pH: 6.5–7.5
- Hardness: 5–25 dGH (soft to moderately hard)
The pleco’s native river range covers considerable environmental variation, which translates into genuine adaptability in captivity — they tolerate a broad band of pH and hardness. What they will not forgive is poor water quality: high ammonia and nitrite from an undersized or overwhelmed filter will cause skin lesions, lethargy and eventually death. Weekly water changes of 25–30% and a filter rated for at least twice the tank volume are the baseline. Test water regularly, especially in a newly set-up tank.
Moderate current is appropriate — replicating the turbid, moving river water of their origin. Stagnant, warm tanks with heavy pleco waste are a recipe for bacterial outbreaks.
What do Common Plecos eat?
Common plecos are omnivores with a strong lean toward plant matter and biofilm. In the wild they rasp algae, biofilm, decaying wood and fallen organic matter from submerged surfaces. In captivity they should be fed:
- Sinking algae wafers and catfish pellets — the daily staple, offered after lights-out when plecos become active.
- Blanched vegetables — zucchini (courgette), cucumber, spinach, sweet potato and peas are all accepted; weight them down with a fork or clip so they sink to the bottom.
- Driftwood — always present in the tank; plecos rasp it continuously and it is a dietary requirement, not just decor.
- Occasional protein — sinking shrimp wafers or frozen bloodworm can supplement the diet, though plant matter should dominate.
Do not assume your pleco is feeding on tank algae alone. A large pleco will graze any algae clean quickly, then begin rasping the slime coat of slow or sleeping fish if it is hungry. Feed a proper diet every evening.
Are Common Plecos aggressive — and what fish can live with them?
Common plecos have a peaceful temperament toward mid-water and upper-level fish. They coexist quietly with the vast majority of community species — cichlids, large barbs, tetras, gouramis — provided the tank is large enough. The caveat is territorial behaviour toward their own kind and toward other bottom-dwellers occupying the same space. Two common plecos in the same tank will fight for territory once they mature; keep only one unless the system is very large.
Large plecos can also inadvertently damage slow, flat-bodied fish (discus, large goldfish) by latching onto them to rasp the protective slime coat — a stress response to hunger. Preventing this is straightforward: feed the pleco properly every day.
For a full breakdown of pairings that work and ones to avoid, see Common Pleco tank mates.
How do you tell male and female Common Plecos apart?
Sexing common plecos is possible but requires a trained eye. Males develop odontodes — stiff, bristle-like spines — on the pectoral fin rays and on the interopercular plates (the cheeks). These become visible as the fish matures, typically from around 15 cm (6 in) onward, and are clearly tactile if you run a finger (carefully) along the pectoral fin. Males may also have a slightly broader, flatter head.
Females are generally rounder and wider across the abdomen when viewed from above, particularly when carrying eggs, and lack the pronounced odontodes of males.
In a dealer’s tank of juvenile plecos this distinction is essentially impossible, and even in home aquaria sexing remains uncertain until fish are well grown.
How do Common Plecos breed?
Breeding common plecos in a home aquarium is very hard — deservedly the highest difficulty rating in the hobby. In nature, the male excavates a burrow in a riverbank or clay substrate, the female deposits eggs inside, and the male guards and aerates the clutch alone until the fry are free-swimming. Replicating a riverbank burrow in an aquarium is the primary challenge.
Specialist breeders have had success using large, tight-fitting clay or PVC tunnels buried in a sand/clay substrate mixture, with substantial water flow and conditioning the pair on high-protein live foods. Even then, spawning is inconsistent and raising fry to sellable size requires months of dedicated effort. For the vast majority of hobbyists, breeding is not a realistic goal — pleco juveniles in shops come almost entirely from large-scale commercial fish farms in Southeast Asia and Florida.
What are common Common Pleco diseases?
The most frequent health problems are:
- Ich (white spot disease) — small white cysts on the skin and fins; caused by the parasite Ichthyophthirius multifiliis, typically triggered by chilling or poor water quality.
- Bacterial infections / body lesions — red patches, ulcers or open sores, often secondary to physical damage (fighting, net injury) or chronically poor water; large plecos are particularly vulnerable when kept in dirty or cramped conditions.
- Anchor worm and fish lice — external parasites more common in fish from outdoor ponds or certain importation routes; visible to the naked eye on the body surface.
- Nutritional deficiencies — hollow belly, faded colour and lethargy in plecos that are not receiving sufficient plant-based food; easily prevented with a varied diet and driftwood.
- Constipation and gut stasis — seen in plecos fed too much protein and too little fibre; blanched vegetables and continuous driftwood access are the prevention.
Prevention across all conditions comes down to the same fundamentals: excellent filtration, regular water changes, a temperature-stable tank and a properly varied diet.
Health note: Disease diagnosis and medication dosing are outside the scope of a care profile. If your pleco shows symptoms, cross-reference against a reputable veterinary or fish-health source before treating.
How long do Common Plecos live?
A common pleco in good conditions lives 10–15 years — one of the longer lifespans in the freshwater hobby. This is worth taking seriously before purchase. The 5 cm juvenile you bring home today is a commitment to a decade or more of care, a 380 L tank and an ongoing investment in quality food and filtration. Owners who make that commitment report enormously rewarding fish: plecos develop recognisable personalities, learn feeding routines and become one of the more interactive bottom-dwellers available in the hobby. Owners who underestimate adult size are responsible for the thousands of plecos surrendered to public aquariums and fish rescues every year — the fish outlives the impulse buy by a decade.
Frequently asked questions
How big does a common pleco really get?
In a spacious aquarium a common pleco typically reaches 35–45 cm (14–18 inches) and can exceed 60 cm in the wild. That is far larger than the 5 cm juveniles sold in pet shops, which is why so many end up donated to aquariums or released (never release fish into the wild). Plan for a 380 L (100 gal) minimum for an adult.
Does a common pleco eat algae or does it need extra food?
It rasps algae but cannot live on algae alone. Supplement daily with sinking algae wafers, catfish pellets, and blanched vegetables such as zucchini and cucumber. Driftwood is also important — plecos rasp it for fibre and gut bacteria, and it should be present in every pleco tank.
What you need to keep a common pleco
The baseline is a heated, filtered 380 L+ tank: a reliable heater to hold 22–28 °C (72–82 °F), a gentle filter that won't batter a common pleco in the current, and a tight-fitting lid. Cycle the tank fully before adding any fish.
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