Dictionary of Ichthyology
This dictionary of ichthyology contains specialist terms used in the teaching of undergraduate students. The terms are arranged alphabetically for ease of reference.
In addition to ichthyology, terms from hydrobiology, zoology, anatomy, fish farming and other related disciplines are included.
Where terms have different interpretations, we have assigned the most common interpretation in our view.
This dictionary is constantly being added to and modified.
If you do not agree with the above interpretation of the Terms, please explain your understanding in the comments to these Terms.
We invite you to participate in the development of a modern ichthyological vocabulary.
We will consider any criticism and take it into account when describing dictionary terms.
Nelma
Nelma (Stenodus leucichthys nelma) is a Siberian subspecies of the genus Nelma in the whitefish fami..
Neritic fish
Neritic fishes - marine fishes inhabiting coastal sea waters up to 200 m depth, mainly above the she..
Nervous system
The nervous system is a set of nerve cells and other structures that ensure the work of all organs a..
Neuston
From the Greek neustos- floating.Neuston - a set of organisms living directly within the surface fil..
Nictitating membrane
The nictitating membrane is the third movable eyelid at the front corner of the eye of some sharks.A..
Non-retractable mouth
Non-retractable mouth - characterized by fixed connection of the bones of the upper jaw with the sku..
Northern pike
The northern pike (Esox lucius) is a freshwater fish of the pike family. It has an elongated, arrow-..
Nostrils
Nostrils are paired nasal openings located in front of the eyes and not communicating with the phary..
Notochord
Greek χορδή, "string," dorsal string, notochord.The notochord is a strong and flexible formation tha..
Nototheniidae
Nototheniidae is a family of fishes of the order Perciformes. 15 genera, more than 50 species (gray,..
Octopus
Latin Octōpoda, from Ancient Greek ὀκτώ "eight" and πούς "foot".Octopods (Octopoda) are a subdivisio..
Olfactory organs
The olfactory organs are paired olfactory sacs that open outward through the nostrils on the front o..
Oligochaeta
Latin Oligochaeta; from Dr. Greek ὀλίγος 'little' and Dr. Greek χαίτη 'hair'.Oligochaeta - small bri..
Oligosaprobes
From oligo..., Greek sapros - rotten and bios - life).Oligosaprobes are organisms living in slightly..
Oligosaprobic pond
A reservoir with a low content of organic matter and carbon dioxide, high oxygen saturation and the ..