L - Aquarium Dictionary

Updated August 12, 2019
Author: Mike - FishLore Admin
Social Media: FishLore on Social Media

Aquarium Fish Definition and Glossary

Labyrinth Organ :
is a specialized organ in the anabantid species that allows them to take in oxygen at the water surface directly from the air.

Larvae :
after fertilization, the first stages of life for fish and invertebrates. The larvae looks different from the adult form of the organism.

Lateral Line :
along with being able use their vision to detect fish, food and other objects, Fish can use their lateral line to detect vibrations and other objects in the water. The lateral line runs the length of the fish, from the head to the tail. It is located in the upper part of the body, starting at the head of the fish.

Laterite :
is a planting soil that is rich in nutrients and minerals that is used for freshwater aquarium plants.

Lepidophagy :
a feeding behavior in some fish species where the fish will eat the scales off of other fish.

Lettuce Clip :
a clip with a suction cup used to attach to the inside walls of the aquarium used to feed fish. You can attach seaweeds such as nori for your herbivorous fishes. See:
Lettuce Clip on Amazon

abbreviation for Local Fish Store.

abbreviation for Light Emitting Diode. Is LED aquarium lighting the future of aquarium light systems? They are still rather expensive at this time (2007) but prices are expected to come down. These LED lights run cooler (no need for chillers?), use less energy and can provide many different lighting configurations. These LED's present some exciting possibilities but prices need to come way down before more hobbyists start using them. For one of the more popular freshwater aquarium LED light fixture, see:
Led Light
LED Light on Amazon

Levamisole :
is a medication that is used in the treatment of camallanus worms. Here is a good thread on treating camallanus worms. Levamisole can sometimes be hard to find locally, but you can buy it below:
Levamisole on Amazon

abbreviation for Liters Per Hour and usually refers to the flow rate of aquarium filters or power heads.

abbreviation for Large Polyped Stony Corals or Local Pet Store.

Light Meter :
a device that measures light intensity. Also see lux meter.

Limewood Diffuser :
used like an air stone, a limewood diffuser produces fine bubbles and is sometimes used in protein skimmers, air bubblers, or in the lift tubes of an undergravel filter.

Livebearer :
refers to fish that have free swimming fry. Also see: Livebearer Fish Species, Guppy, Mollies, Platies and Swordtails.

Live Rock :
is rubble that has broken off the coral reef structure and is inhabited by many forms of life that can be beneficial in the saltwater aquarium. Good quality live rock is extremely porous and provides a great location for colonizing bacteria that aid in the aquarium nitrogen cycle. Read the article on live rock. Also see:
Live Rock
Live Rock on Amazon

Live Sand :
is sand that is used in saltwater aquariums that is populated with beneficial bacteria, invertebrates and other microscopic life forms that aid in the breakdown and conversion of elements within the aquarium. Live sand can be expensive to purchase (per pound) and a saltwater tank does not need to be stocked with live sand from the start. There is much skepticism within the trade regarding live sand manufacturers claims about this product. How can these organisms possibly stay alive in sub-optimal temperatures and little to no oxygen during transport? Regular sand (for saltwater aquariums) is much cheaper (per pound) and will quickly become populated with these beneficial organisms when using live rock over a period of time.
live sand
Live Sand on Amazon

LR :
abbreviation for Live Rock.

LS :
abbreviation for Live Sand.

Lumens :
is the total output of a light source.

Lux :
is a measurement of the intensity of the light. Sunlight on a clear day is approximately 32,000 lux. 1 lux = 1 lumens/meter2

Lux Meter :
is a device used to measure lux, or light intensity in the aquarium. Coral keepers may use them to determine ideal locations for coral placement within the tank. It's also good to use a lux meter to determine if your aquarium light can provide enough lux for the corals you want to keep. See the meter below:
Lux Meter
LUX Meter on Amazon