Blue Phantom Pleco
Hemiancistrus sp. (L128)
Also known as: Blue phantom, L128
Quick Facts
- Adult size: 16-18 cm (6.3-7.1 inches)
- Minimum tank size: 200 litres (53 gallons)
- Lifespan: 8–12 years
- Temperament: peaceful
- Swimming level: bottom
- Diet: omnivore
- Minimum group size: 1
- Difficulty: intermediate
Water Parameters
- Temperature: 25–30°C
- pH: 6–7
- Hardness (GH): 54–179 ppm (3–10 dGH)
Values above are general hardness (GH). For carbonate hardness (KH), the buffer that keeps pH stable, see the water parameters guide.
Care Summary
A deep, inky-blue pleco dusted with small pale spots, the blue phantom (L128) is prized for a colour that is genuinely rare among fishes. It comes from the fast, oxygen-rich Rio Orinoco near Puerto Ayacucho in Venezuela, and it wants those conditions in the tank: warm water of 25 to 30 degrees, strong flow, and high oxygen, kept just on the soft side of neutral. It reaches around 18cm, so it needs a tank with real swimming and grazing space. Its diet leans towards protein, so alongside vegetables and algae it should get regular meaty and prepared sinking foods. Almost all blue phantoms in the trade are wild-caught, as the species is rarely bred, so expect a fish that appreciates mature, stable water and settled surroundings. A beautiful and relatively hardy specialist for an intermediate keeper with a well-filtered tank.
Tankmates
Peaceful towards other species and a fine companion for a warm community of rainbowfish, larger tetras, peaceful cichlids such as angelfish and German blue rams, and corydoras. It is territorial towards other bottom dwellers, so keep one per tank and give it caves and wood to claim, with strong flow and high oxygen. Avoid large or aggressive cichlids and persistent fin-nippers.
Compatible with
- Boeseman's Rainbowfish
- Congo Tetra
- Angelfish
- German Blue Ram
- Sterbai Corydoras
- Rummynose Tetra
- Pearl Gourami
Avoid keeping with
- Large Cichlids
- Fin Nippers
- Common Pleco
Common Problems
- sensitivity to low oxygen and warm, stale water
- being underfed, as it needs protein and not just algae
- territorial disputes with other plecos and bottom dwellers
- acclimation losses as a mostly wild-caught fish
Sources: planetcatfish.com, seriouslyfish.com · Last updated: 2026-10-04