Should I buy it?
Common Pleco
Hypostomus plecostomus
Typical trade / ID note: Hypostomus plecostomus (approximation)
Also known as: suckermouth catfish, plecostomus, Pleco, Hypostomus (common name)
Fishori provides conservative planning guidance, not guarantees.
Based on typical aquarium care sources; trade names can be ambiguous, so details may vary between setups. Use the numbers here as planning defaults — your room, water, and routine still shape real-world outcomes.
Sold at 8 cm, grows to 45 cm or more in three to five years, and produces the waste output of a small dog. Get a bristlenose pleco instead.
Best for
Aquarists with 400L+ tanks who specifically want a large, slow, plant-eating catfish. And have a plan when it outgrows everything.
Avoid if
You are a beginner, your tank is under 300L, you want plants, or you have no plan for a 45 cm fish in three years.
Top things that go wrong
- Grows large or needs a very big footprint. Common Pleco is often sold at sizes that hide adult length (~60cm on file) and a published minimum near **600L**. Shop tanks are not adult housing.
- Shrimp & snails. Shrimp: compatible in most setups. Cherry shrimp and other dwarf species coexist with peaceful small fish, though baby shrimp are food for almost any fish that gets to them.
Common mistakeA 4 cm free pleco in 100L. It reaches 40 cm in year two and outgrows most home tanks.
Common trade-name warning
This fish is often sold under different names or species variants. Care guidance is based on typical aquarium examples rather than a single exact species. The label "common pleco" may cover several Hypostomus and L-number look-alikes; size and care still demand a very large system.
What most shops don't tell you
- 1.Large minimum volumes still need real footprint: length and width for turning matter as much as the litre number on a sticker.
- 2.A 4 cm 'free pleco' in 100L. By year two it is 40 cm. Either rehomed, or chewing wood and silicone.
- 3.Relying on a bottom fish to 'eat' the nitrate spike. Only water changes and stocking discipline fix that.
- 4.Almost always sold incorrectly for small tanks. A common pleco in a 60L tank is a welfare issue, not a stocking choice. Buy only if you have a 600L+ tank, or a plan for when it outgrows that.
- 5.Common plecos outgrow almost all home tanks; plan for adult size and bioload.
About this species
Common plecos grow to 45 to 60 cm in three to five years. The shop sells them as algae eaters at 5 cm. The bag never mentions the 600L+ tank the adult needs.
- Royal pleco500L min · same group, comparable tank size
- Clown Pleco110L min · same fish family
- Siamese Algae Eater100L min · same fish family
- Bristlenose Pleco80L min · same fish family
- Otocinclus60L min · same fish family
- Bala / silver sharkalso intermediate peaceful, similar tank size
- Clown Loachalso intermediate peaceful, similar tank size
- Silver dollaralso intermediate peaceful, similar tank size
- Tinfoil barbalso intermediate peaceful, similar tank size
- Green Terror tank mateslists this fish as a safe and recommended mate
- Jack Dempsey tank mateslists this fish as a safe and recommended mate
- Oscar tank mateslists this fish as a safe and recommended mate
Plan grid
Key limits are shown above; this section adds planning detail: pH band, swim level, bioload and activity, and the radar.
Swim zones
Planning trait chart
Six indices for comparing species on paper before you spend.
- Beginner ease27
- Peacefulness82
- Community fit70
- Small-tank fit16
- Hardiness57
- Energy24
Numbers are deterministic planning indices from Fishori fields — not a scientific score of your individual fish.
Common setup sketches
Conservative patterns from Fishori fields — still run the pair checker for every species you add; sketches are not a stocking guarantee.
Avoid “one of everything” baskets — Common Pleco belongs in a plan built around territory, line-of-sight breaks, and matched water chemistry.
Tank mate intelligence
Almost always: pick a bristlenose (max 12 cm) or rubber-lipped pleco instead. If you keep a common pleco, pair with large robust cichlids in a 600L+ setup.
Pair-level compatibility with this fish as anchor.
Read the blocking rule on each pair page before experimenting.
Do-not-stock combinations on conservative hobby rules.
Compare with
Run a real pair check: Common Pleco + Oscar
- Try Oscar — open the pair check.
- Try Jack Dempsey — open the pair check.
- Try Green Terror — open the pair check.
Behaviour, temperament, and what to watch
Prose and lists come from the same record: read temperament first, then glass-level signals so you are not surprised after day three.
Peaceful as juveniles but become territorial-grumpy adults that will scrape mucus off slow tank-mates like discus and angels at night.
Stress / aggression triggers on file
- Sudden crowding
- Poor water quality
Fin nipping: Not a habitual fin-nipper, but individuals can still test fins under stress or in a crowded tank.
Predation: Not a predator toward similarly-sized community fish. The usual community caveats about mouth size still apply for very small fry or shrimp.
Territory: Holds territory on substrate, in caves, or at the surface film. Break the line of sight with hardscape, and avoid placing the tank where the fish can see its own reflection.
Planted tanks: good — easy plant ideas
In the glass: typical and warning signs
- Often calm on the glass — bursts of movement around food or tank disturbance.
- Clamped fins, gasping at the surface, hiding non-stop, or refusing food after the first week.
- Rapid breathing when parameters swing — fix ammonia/nitrite first, then reassess mates.
- Corner guarding, flaring, or body-blocking — territory is normal until it becomes relentless.
- Separate or rehome if injuries appear, one fish is pinned, or feeding becomes a daily chase.
- If water is stable but behaviour worsens, reduce stocking or remove the highest-impact species first.
Fish behaviour can vary between individuals and tank setups. Always observe new fish closely after introduction.
Care parameters: water, food, inverts, grouping
Chemistry and group rules sit here so you are not re-reading the same line from tank mate or temperament blocks. Swim level is in the plan grid above.
Hardness
variable
Diet
herbivore
Vegetable matter, algae, and plant-based prepared foods. Long-term protein-only feeding causes bloat in herbivorous species.
Shrimp & snails
Shrimp: compatible in most setups. Cherry shrimp and other dwarf species coexist with peaceful small fish, though baby shrimp are food for almost any fish that gets to them.
Kept singly or as a paired setup. Check the species profile before doubling up in one tank.
Breeding behaviour depends on the species. Research before you buy a mixed-sex group of this fish.
- Hold 22 to 30 °C steadily on a real thermometer, not the dial on the heater.
- Aim for pH 6.5 to 7.5 and a hardness you can re-test in two weeks. A one-time strip in the shop car park is not a water test.
- Footprint: short wide tanks and tall narrow tanks fish differently for the same volume. Match the tank shape to the swim pattern, not just the litre count.
- Tank volume meets or exceeds 600L published minimum for adults.
- Heater can hold 22–30°C without cooking cooler-water tank mates.
Explore and stocking hubs
Same library as the rest of Fishori: tank-mate index for this species, category peers, guides, and litre-based stocking lists where min tank on file is within the hub volume.
Plan with tools
Pair-level rules and multi-fish stocking use the same conservative engine — add this fish in the tank builder only after mates pass pair checks.
Filtration & heating
A 600L minimum tank needs a filter rated for at least 2400L/hr turnover and a heater to hold 22–30°C reliably.
Plant suggestions
Common Pleco does well in planted tanks. Plants compatible with 22–30°C and pH 6.5–7.5:
Profile status: verified · Evidence tier: medium · 3 linked source(s). Fishori does not fabricate citations.
Fishori uses conservative planning rules based on these sources.
Confidence is explained in the summary at the top of this page (same tier as here), not repeated below.
How Fishori evaluates compatibility (same logic as pair and tank tools).
- LiveAquaria. Suckermouth / Common pleco (Hypostomus plecostomus)
Primary: large-aquarium retailer care guidance for the common / suckermouth Hypostomus type; emphasises long-term size and need for a very large system.
- Planet Catfish. Hypostomus plecostomus (Cat-eLog species sheet)
Primary: hobby species sheet: identification pointers, size expectations, and import caveats for the name 'common pleco' in trade.
- FishBase. Hypostomus plecostomus
Secondary: natural distribution and maximum size in the wild; cross-check 'common plec' in shops, which is often a different Hypostomus altogether.
Evidence notes
- Seriously Fish did not provide a retrievable H. plecostomus profile URL; LiveAquaria + Planet Catfish are used as aquarium-facing primaries, with FishBase for wild maximum length. Trade 'common pleco' is a grab-bag of Hypostomus, so the binomial and care numbers may not match a given fish without ID photos.
- FishBase contributes natural-range size and habitat context. Translate those numbers through your heater, your water report, and your tank footprint before stocking.
- All compatibility text reflects typical hobby experience and the Fishori model. Individual fish, shop stress, and the order tank mates are added in can still defy a single-paragraph label.
- Fishori profiles work from typical aquarium trade sizes and hobby care norms. Specialist site checks and literature review for this species are not yet recorded here, so the ranges on this page are planning numbers rather than guarantees.