What are Pleco L-Numbers

Have you ever wondered why Pleco are commonly referred to by an 'L-Number' such as L046?

Scientific Naming of Pleco
The formal naming system of fish is comprised of three parts, The Family, Genus and Species. However, the L-number is not a formal scientific designation for naming pleco. 

For example the Zebra Plecos' scientific name is 'Hypancistrus Zebra' or 'L046'. This fish belongs to the family of fish known as Loricariidae.

Family: Loricariidae 
Genus: Hypancistrus
Species: Zebra
L-number: L046

The scientific naming system was developed and has been used since the late 18th century.
Often naming fish after distinguishing traits, behaviors or features exhibited by the fish. In this case, the Zebra Pleco has Black and White (or white and Black) stripes like a Zebra. So was given the species name 'Zebra'.

There are currently 92 different Genera in the Loricariidae family. With the Loricariidae containing over 680 different species of Pleco. Hypancistrus is just one of those genera, a small genus of just 8 pleco. With 2 species being discovered as recently as 2017. 


Why the L-Number?
As fish keeping became more popular during the 20th century, fish began being mass exported from South America for the aquarium trade. This included many species of Plecostomus. 
New species of Pleco were being discovered and exported quicker than they could be scientifically classified and named. This caused fish to be given many names and caused confusion among importers, exporters and aquarium hobbyists. 

The first official L-Number was given to a pleco in 1988. L coming from the family word 'Loricariidae'. This is not a formal scientific designation for naming the fish, but was used as a way of mutually identifying a fish.

Some pleco were identified with the name number and some pleco were identified with more than one number so it is important to check the scientific name for the fish when purchasing. 

As 2021, there are over 600 documented L-Numbers currently.