Remarks: The L066 king tiger pleco is known from the same area as the L333 Gurupa pleco, the lower Rio Xingu in Brazil. Adults of both fish look heavily similar and are frequently confused for the other. The L066 king tiger pleco differs from the L333 Gurupa pleco in that their base color is much lighter compared to the yellow or tan base color of the L333 Gurupa pleco. The stripes on their fins are also more straight and uniform. The difference in color and pattern are much more obvious in juvenile fish which can sometimes be almost white with disconnected black stripes and spots.

  Recently in 2025, a taxonomic study was conducted on the L066 king tiger pleco along with a number of other similar looking Hypancistrus. This study determined that the plecos under the L-numbers L333, L66, L236, L399 and L400 were all just different variations/localities of the same highly variable new species. This new species name was deemed Hypancistrus seideli. They were named after professional aquarist, Ingo Seidel, who has been a great influence within the hobby and the scientific realm in regards to Loricariids. He especially made an impact in regards to Hypancistrus species so it is very fitting that he get these amazing little catfish named in honor of him. You can read more on this study by clicking .

  The L066 king tiger pleco is a typical Hypancistrus in regards to their care in captivity. They come from rocky areas of pristine, heavily oxygenated, warm, soft, and acidic water and will gradually decline in health in the home aquarium if these conditions are not replicated. Using a high quality filter with a high flow rate along with a heater and frequent water changes will help keep these plecos happy and healthy. Like all known Hypancistrus, the L066 king tiger pleco is a carnivore so they must be fed a varied diet high in protein. Protein rich gel foods like Repashy, bloodworms, and sinking wafers are good choices to feed to meet their dietary needs. 

  To reduce territorial fights and help the L066 king tiger pleco feel comfortable in the aquarium, plenty of snug, rocky caves should be provided for them to hide in. These caves are also where these fish will spawn if all other conditions are just right. They can be a very exciting breeding project as they are such a unique and beautiful catfish. An important thing to note, however, is that it is not wise to house the L066 king tiger pleco with other similar Hypancistrus as they can hybridize with it being near impossible to tell pure fish from hybrids. We encourage anyone who sets out to keep these fish make an effort to ensure captive populations remain pure to preserve this species in light of dam construction in Brazil destroying their natural habitat.