20 long
From The Aquarium Wiki
20 long (20L) is a aquarists phrase used to describe an aquarium tank that holds 76 Litres (20 US G.) of water and is quite 'long'.
This is typically 30" long by 12" deep by 12" high (61 cm x 30 cm x 30 cm).
- See 20 tall (20T).
- 20 US Gallons is 75.7 Litres.