N - Aquarium Dictionary

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

Aquarium Fish Definition and Glossary

nm :
abbreviation for Nanometer.

Nanometer :
abbreviated nm, is one billionth of a meter. It refers to the wavelength of light in aquarium lighting. Different light wavelengths produce different colors. Humans can only view light in the range of 380 nm (violet) to 780 nm (red).

Nauplii :
used in reference to newly hatched brine shrimp, Nauplii are newly hatched free swimming crustaceans.

Nematocyst :
the stinging cell, sometimes poisonous, that cnidarians (corals, sea anemones, jelly fishes) release to capture prey or as a defensive mechanism.

Neo-Therm Heater :
an aquarium heater made by Cobalt Aquatics. It is a flat style heater that is shatterproof. More below:
Cobalt Neo-therm Heater
Neo-Therm Heater on Amazon

NH3 :
see ammonia.

NiloCG :
aquarium supplement manufacturer that makes the popular plant fertilizer called thrive:
Thrive on Amazon

Nitrate :
NO3, occurs toward the end of the aquarium nitrogen cycle and can harm fish in high enough concentrations. In tanks without any form of denitrification, water changes are needed to remove nitrates. You can measure the amount of nitrates in your aquarium water using a test kit:
Nitrate Test Kit on Amazon

Nitrite :
NO2, is the middle step in the aquarium nitrogen cycle where Ammonia is converted to Nitrites and Nitrites get converted into Nitrates. Nitrites are not as harmful to fish as ammonia, but can still be deadly if the fish are exposed for prolonged periods. You can measure the amount of nitrites in the aquarium water by using a test kit:
Nitrite Test Kit on Amazon

Nitrofurazone :
is a fish medication used to treat a wide variety of bacterial infections. API Furan 2 is an easily acquired product that can be used:
Furan 2
Furan 2 on Amazon

Nitrogen Cycle :
sometimes called new tank syndrome, the aquarium nitrogen cycle refers to the conversion of Ammonia to Nitrite and then Nitrites to Nitrates by beneficial bacteria that form inside the aquarium and in the filtration system. Also see: Aquarium Nitrogen Cycle

NO :
abbreviation for Normal Output fluorescent lighting.

NO2 :
see Nitrite.

NO3 :
see Nitrate.

stands for New Life Spectrum and is a type of fish food. It gets rather good reviews among hobbyists. For more info on this food :
New Life Spectrum
NLS Food on Amazon

Nocturnal :
refers to an animal or fish that rests during the day and becomes more active at night or in darkness. The opposite of diurnal.

Nori :
a fish food (humans eat it too!) that is used to feed fish that are primarily herbivores. Often sold in dried sheets, it is supposed to be nutritionally superior to many other vegetable type foods that are often fed to fish. You can use a vegetable clip to feed the fish or put it under the live rock in the tank and let the fish nibble at it. Many saltwater tangs like to eat nori too. It is usually cheaper to buy nori in bulk online:
Nori Seaweed on Amazon

nsw :
abbreviation for Natural Salt Water.

New Tank Syndrome - More of an old school term from when less was known about the aquarium nitrogen cycle.

Nuchal Hump :
is the large hump on the backside of the head in some cichlid species. The purpose of this hump has not been scientifically determined, but is thought to be used for attracting mates.