The Green Phantom Pleco L200 (Hemiancistrus subviridis) is a striking L‑number catfish known for its deep olive‑to‑emerald green coloration, often highlighted by subtle yellow spotting and bright yellow margins on the dorsal and caudal fins. Originating from the fast‑flowing, highly oxygenated tributaries of the Orinoco River on the Colombia–Venezuela border, this species is naturally adapted to clean, well‑filtered water and rocky environments with strong current.​

Appearance and behaviour

• The body shows a smooth, uniform green or lemon‑lime tone that stands out beautifully under modern LED aquarium lighting.​

• Large, fan‑like dorsal and pectoral fins give the fish a graceful, “sailing” posture as it glides along glass, rocks, and driftwood surfaces.​

• This pleco is generally peaceful and spends most of its time on the bottom or attached to décor, making it an excellent companion for calm community fish that occupy the mid‑ and upper water layers.​

Tank size and setup for beginners

• Recommended minimum tank size is around 200 litres to provide adequate floor space, stable water parameters, and enough hiding spots for a fully grown specimen of 15–20 cm.​

• Provide rounded rocks, caves, and driftwood to mimic its natural riverbed habitat and offer secure retreats, which helps reduce stress and shyness, especially in newly introduced fish.​

• A moderate to strong water flow created by an efficient external filter or additional powerhead is strongly recommended to replicate the oxygen‑rich rivers where this species occurs.​

Water parameters and filtration

• Ideal water temperature ranges between 24 and 30 °C, with a slightly acidic to neutral pH of about 6.5–7.5 and soft to moderately hard water.​

• High filtration capacity and regular partial water changes are essential, as this species is sensitive to poor water quality and benefits greatly from stable, low‑waste conditions.​

• Ensure strong surface agitation or supplemental aeration, as these plecos come from environments with intense water movement and high dissolved oxygen levels.​

Diet and feeding guidance

• While often regarded as an algae‑grazing fish, the Green Phantom Pleco is best described as an omnivorous grazer that should receive a varied diet beyond natural tank algae.​

• Offer high‑quality sinking algae wafers, spirulina‑based tablets, and blanched vegetables such as courgette, cucumber, and spinach to support healthy digestion and coloration.​

• Supplement with occasional protein‑rich sinking pellets or frozen foods (such as bloodworms or shrimp‑based diets) to ensure balanced nutrition, especially for growing juveniles.​

Compatibility and suitability for beginners

• The species is peaceful and generally ignores other fish, making it suitable for community tanks with tetras, rasboras, peaceful cichlids, and other non‑aggressive tank mates that enjoy similar warm, soft water.​

• Avoid keeping it with fin‑nipping species or very territorial bottom dwellers that may compete aggressively for space and hiding spots.​

• With proper introduction, stable water conditions, and appropriate hiding places, this pleco is suitable for beginner aquarists who are comfortable maintaining a medium to large tank and performing regular maintenance.​