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Fish Terminology
A
- Abdomen: belly
- Abdominal: pertaining to the belly
- Actinosts: a series of bones at the base of the pectoral rays
- Acuminate: tapering gradually to a point
- Acute: sharp, pointed
- Adipose: fleshy or fatty. Often applied to small rayless fins and to eyelids
- Adipose fin: a small fleshy fin which lacks fin rays. See adipose.
- Adnate: joined together
- Adpressed: pressed against the body
- Aestivate: to be inactive during warm dry periods
- Airbladder: see swimbladder
- Alimentary canal: the passage through which food passes, starting at the mouth and ending at the anus
- Anal: pertaining to the anus or anal fin
- Anal fin: the fin on the median line behind the vent
- Anal fin origin: the most anterior point of the anal fin base
- Ankylosed: grown firmly together
- Anterior: relating to the front portion
- Antrose: turned forward
- Anus: the external opening of the intestine, the vent
- Approximate: placed close together
- Asperity: roughness of surface
- Asymetrical: without symmetry
- Attenuate: tapering to a point, usually in reference to a tail
- Axillary: pertaining to the axilla or upper angle of the pectoral fin
- Axillary process: an enlarged, pointed scale projecting from the insertion of the pectoral or pelvic fin.)
B
- Barbel: an elongated fleshy projection, usually about the head
- Basal: pertaining to the base, at the base
- Base: the part of a projection, (commonly a fin), which is connected to the body
- Bathypelagic: living at a depth between 1000 m and 4000 m, but well off the bottom
- Benthic: bottom-dwelling, living on the sea bed
- Benthopelagic: pertaining to fishes that swim just above the seabed at depths below about 200 m (the edge of the continental shelf)
- Bicuspid: having two cusps or points
- Bifid: cleft in two
- Bifurcate: forked, or divided into two parts or branches
- Branchial: pertaining to the gills
- Branchial aperture: the gill opening
- Branchiostegals, Branchiostegal ray(s): bony rays supporting the gill membranes behind the lower jaw
- Bristle: a stiff hair-like projection
- Buckler: a bony shield
- Bycatch: species other than the target species that are caught incidentally in a trawl
C
- Canines: conical teeth which are longer than other teeth
- Caniniform: shaped like a canine tooth, conical in form
- Carapace: a horny or bony covering encasing the body
- Carinate: keeled, having a ridge along the middle line
- Cartilage, Cartilaginous: gristle, gristly
- Caruncle: a fleshy outgrowth
- Caudal: pertaining to the tail
- Caudal fin: the tail fin
- Caudal peduncle: the region of the body between the end of the anal fin and the base of the caudal fin
- Ciliated: fringed with eyelash-like projections
- Cirri: small, thin appendages, often subdivided into branches.
- Cirrus: singular of cirri (see above)
- Claspers: the external reproductive organs of male sharks, rays and chimaeras
- Coalesced: grown together
- Compressed: flattened laterally
- Confluent: joined together
- Conical: cone shaped, with a cylindrical base and a pointed tip
- Corselet: a scaly covering behind the pectorals of some fishes
- Continental shelf: the region of the seabed extending from the coast down to a depth of around 200 m
- Continental slope: the region of the seabed that slopes down from a depth of around 200 m (the edge of the continental shelf) to around 2000 m
- Countershading: body colouration which is dark above and lighter below
- Cranium, Cranial: the skull, pertaining to the skull
- Crenulate: having the edge slightly scalloped
- Cusp a point or projection on a tooth
- Cutaneous: pertaining to the skin
- Ctenoid: rough-edged
- Cycloid: smooth-edged
D
- Deciduous: easily removed / rubbed off, temporary, falling off
- Demersal: living on or near the sea bed
- Dendritic: resembling a tree or shrub
- Denature: the "unfolding" of a protein resulting in a lessening of its biological properties. In the case of some fish toxins, denaturing with hot water can lessen painful symptoms.
- Dentate: with tooth-like projections
- Denticle, denticulate: a little tooth, having an edge with small projecting teeth, the placoid scales of cartilaginous fishes
- Depressed: flattened from top to bottom
- Dermal: pertaining to the skin
- Dewlap: a fold of loose skin
- Disc: the flattened head and body of various fishes such as stingrays, which also commonly includes the pectoral and ventral fins
- Distal: remote from the point of attachment
- Dorsal: pertaining to the back
- Dorsum: the upper (dorsal) surface of the head or body
- Dorsal fin: the fin on a fish's back
- Dorsal fin origin: the most anterior point of the dorsal fin base
E
- Elasmobranchs: cartilaginous fishes - sharks, rays and allies
- Electrocyte: a cell that generates electricity
- Elongate: extended, drawn out
- Emarginate: with the margin slightly hollowed
- Endemic: restricted to a particular region, for example endemic to Australia
- Entire: with a smooth margin
- Epibenthic: referring to organisms living on the bottom surface
- Epipelagic: referring to organisms living in the region between the surface and 200 m depth
- Erectile: capable of being raised or erected, often referring to spines
- Esca: the lure or "bait" on the end of the illicium of some anglerfishes and relatives
- Estuarine: living in estuaries
- Etymology: The study of word origins and derivation.
F
- Falcate: scythe-shaped, long, narrow, and curved
- Falciform: curved like a scythe
- Filament: a slender or thread-like structure
- Filiform: thread-like
- Fimbriate: fringed at the margin
- Finlet: a small fin, positioned behind the dorsal or anal fins, that is supported by a ray or rays
- Fluviatile: living in rivers
- Fork length: The length of a fish as measured from the tip of the snout to the fork of the caudal fin. Often used for angling species.
- Free rear tips (of fins): the posterior tip of the fin that is closest to the most posterior point of the fin base
- Frontal ridge: a ridge running along the top of the head along the midline
- Furcate: forked
- Fusiform: tapering towards both ends
G
- Gill arches: the bony arches to which the gills are attached
- Gill cover: or bony flap that covers the gills, the operculum
- Gill filaments: a series of projections along the posterior edge of the gill arch, the site of gas exchange
- Gill membranes: membranes covering the gill openings, attached to the branchiostegals
- Gill opening: opening behind each operculum, leading to the gills
- Gill rakers: a series of appendages along the anterior edges of the gill arches
- Gills, Branchiae: organs for breathing the air contained in water
- Glossohyal: the tongue bone
- Gonads: the sexual organs which produce eggs or sperm
- Gonopodium: a modification of the anal fin of some male fishes, that is used to transfer reproductive products to the female
- Gravid: Sexually ripe
- Gular region: pertaining to the region behind the chin and between the sides of the lower jaw
H
- Heart: the large muscle which pumps blood around the circulatory system
- Head length: the distance from the tip of the snout (or upper lip) to the most posterior point of the opercular margin
- Herbivore: an animal that eats plants
- Heterocercal: pertaining to the shape of a tail with a long upper lobe and a shorter lower lobe
- Homology: similarity of features based on common evolutionary descent
- Hyperostosis: a condition resulting in enlargement of areas of bone.
- Hyaline: translucent or transparent
- Hypural joint: the joint between the caudal fin and the last of the vertebrae
- Hypural plate: the flattened bony plate at the posterior end of the vertebral column, formed from parts of the posterior vertebrae.
I
- Ichthyocide: a substance used to kill (and usually collect) fishes
- Ichthyoplankton: fish eggs and larvae
- Illicium: a "fishing rod-like" appendage on the head, usually a modified dorsal fin spine
- Imbricate: overlapping, like the shingles on a roof
- Incised: with a notched margin (often referring to fin membranes)
- Incisors: the front or cutting teeth
- Inferior: pertaining to the lower side (usually of the head)
- Interdorsal: between the dorsal fins
- Interorbital: the space between the orbits
- intromittent organ: a structure to facilitate sperm transfer in some internally fertilizating species
- Iris lappet: a fleshy flap or lobe-like structure in the eye, short and rounded, simple or multiply branched.
- Isthmus: the fleshy projection of the body separating the gill openings
J
- Jugular: pertaining to the throat
- Junior synonym: where more than one scientific name has been used to describe a species, all but the oldest name (the senior synonym) are junior synonyms.
- Juxtaposed: placed near together
K
- Kidneys: organs involved in excretion and regulation of water balance
L
- Lanceolate: spear-shaped, gradually tapering toward the extremity
- Labial: pertaining to the lips
- Labial furrows: shallow grooves around the lips
- Labial papillae: small fleshy projections around the lips
- Lateral: at or toward the side
- Lateral line: a series of muciferous tubes forming a raised line along the side of the body (view 512kb pdf on the X-ray Mag website)
- Liver: a digestive and storage organ
- Longitudinal series (scales): the number of scale rows above the lateral line from the first pored lateral line scale to the caudal fin base.
- Lunate: shaped like a crescent moon, with long upper and lower lobes
M
- Mandible: the lower jaw
- Maxilla, Maxillary: the upper jaw, or pertaining thereto
- Maxillae, Maxillaries: the hindmost bones of the upper jaw; preceded by the premaxillaries
- Median, medially: pertaining to the middle
- Median fins: fins located on the median line of the fish; the dorsal, anal and caudal fins
- Mediolateral: between the middle and the sides
- Mesocoracoid: a bone of the pectoral arch or shoulder girdle
- Mesopelagic: refers to the region of the open ocean between 200 m and 1000 m in depth
- Mesopelagic fishes: fishes that live in the mesopelagic zone
- Midwater: the middle stratum of water, well below the surface and well above the seabed. See also mesopelagic.
- Midwater fishes: fishes that live in the midwater
- Molars: blunt and rounded grinding teeth
- Morphology: form and structure of an organism
- Muciferous: producing or containing mucous or slime
- Myotomes: blocks of lateral trunk muscles
N
- Nape: upper surface of the body behind the head and before the dorsal fin
- Nasal: pertaining to the nostrils
- Nasoral: between the nostrils and mouth
- Nictitating membrane: an inner eyelid
- Notochord: a rudimentary of embryonic spinal column
- Nuchal: pertaining to the nape
O
- Obsolete: faintly marked, scarcely evident
- Obtuse: blunt
- Occipital: pertaining to the posterior part of the skull
- Ocellus: an eye-like spot
- Ocular: pertaining to the eye
- Oesophagus: the gullet
- Olfactory organs: the organs used for smelling, commonly beneath the nostrils
- Omnivore: an animal with a diet that consists of both plant and animal material
- Opercule, operculum: the bony flap that covers the gills
- Opercular: pertaining to the operculum
- Opercular spine: spine projecting from the operculum (view the fish figure)
- Orbit: the eye socket
- Origin: the most anterior point of a fin base
- Osseus: bony
- Osteological: pertaining to bones
- Osteology: the study of bones
- Ovate: egg-shaped
- Oviparous: a species that produces eggs that are hatched outside of the body of the female.
P
- Palate: the roof of the mouth
- Palatines: the bones on each side of the palate
- Papilla (papillae): a small fleshy projection(s)
- Papillose: covered with papillae
- Pectoral: pertaining to the breast
- Pectoral fins: the anterior or uppermost of the paired fins, which correspond to the anterior limbs of the higher vertebrates
- Pectoral girdle: the bones to which the pectoral fin is attached
- Peduncle: usualy referred to as the caudal peduncle, the region of the body between the end of the anal fin and the base of the caudal fin
- Pelagic: living on or in the open seas
- Pelvic girdle: the bones to which the ventral fins are attached
- Pelvic fins: paired fins behind or below the pectoral fins
- Peritoneum: the membrane lining the abdominal cavity
- Pharyngeal bones: bones behind the gills in the oesophagus or gullet
- Pharyngeal teeth: teeth within the pharynx
- Pharynx: the back part of the throat, into which the gill slits open
- Photophore: a circular light-producing organ on the surface of a fish
- Piscivorous: an organism that feeds upon fishes
- Planktivore: an animal with a diet that consists mainly of plankton
- Posterior: towards the hind end of the fish
- Postorbital: behind the eye
- Precaudal: anterior to the tail portion
- Prehensile: adapted for holding, such as the tail of a seahorse
- Premaxillaries: two bones forming the front portion of the upper jaw
- Preocular spine: spine positioned above and in front of the eye
- Preopercle, preoperculum: the bone between the cheek and the gill cover
- Preopercular spine: spine projecting from the preopercule (see preopercle) (view the fish figure)
- Preorbital: the area under and in front of the eyes
- Protractile: capable of extending forward
- Protrusible: capable of extending forward, often referring to the jaws of fishes
- Proximal: nearest
- Pseudobranchiae: small gills developed on the inner side of the gill cover
- Pseudoclasper: stiff ossified lobes or prongs in the tip of the intromittent organ
- Pterygiophore: an internal cartilage or bone that supports a median fin ray or spine
- Pyloric caecae: finger-like pouches connected with the alimentary canal (the gut)
R
- Ramus: one branch or one half of the jaw
- Ray: a jointed rod which supports a fin
- Retrose: turned backward
- Rostrum: a projecting snout or beak
- Rugose: rough
S
- Scalation: pertains to the pattern/arrangement/presence of scales
- Scute: any external horny or bony plate
- Senior synonym: the oldest name used to describe a species
- Serrate: notched like a saw
- Setae: bristles or hairs
- Sexual dimorphism (sexual dimorphism): differences in physical appearance between the sexes
- Soft dorsal: the posterior part of the dorsal fin which is composed of jointed rays
- Spatulate: shovel-like; having a broad, flat and rounded shape
- Spine: a sharp projecting point; an unjointed support in the anterior portions of the dorsal and anal fins
- Spinous, spiniform, spinate: spine-like or composed of spines
- Spinous dorsal: the anterior part of the dorsal fin supported by spines
- Spiracles: respiratory openings behind the eyes in sharks and rays
- Standard length (SL): the length of a fish measured from the tip of the snout to the posterior extremity of the hypurals, the expanded bones at the end of the backbone that support the caudal fin
- Sub- (a prefix): less than, somewhat, not quite, under
- Submarginal: almost at the edge
- Suborbital: below the eye
- Superior: above or on the upper surface
- Supracleithrum: the bone forming a connection between the back of the skull and the pectoral girdle
- Supralateral: above the side
- Supramaxillary: a supplemental bone lying along the upper edge of the maxillary
- Supraocular: positioned above the eye
- Supraorbital: above the eye
- Supraorbital tentacle: a flap or filament of skin positioned above the eye
- Suprascapular: a bone uniting the shoulder girdle with the skull
- Suture: the line of union of two bones or plates
- Symphysis: point of junction of the two sides of the jaw
- Symmetrical: similarly arranged on both sides
- Synonym: a different word having the same or a similar meaning
- Swimbladder: a sac filled with gas, lying beneath the backbone
- Symbiosis: used to describe any association between two organisms. From a Greek word meaning 'living together'.
- Symphysis: the junction of two bones of body elements, often used to describe the middle point at the front of the jaws
- Synonym: one of two or more names that have been used to describe the same species
- Systematics: The study of the evolutionary and genetic relationships between organisms.
T
- Taxonomy: the science of classifying organisms
- Teleost: a large group containing most of the bony fishes
- Terminal: at the end
- Tessellated: marked with little checks or squares, like tiles
- Thoracic: pertaining to the chest
- Thorax: the chest region, just behind the head
- Total length: the length from the tip of the snout to the tip of the tail
- Transverse: crosswise
- Trilobate: with three lobes
- Tricuspid: with three cusps or points
- Truncate: terminating abruptly, as if cut off square
- Trunk: the region of a fish between the head and tail, or the last gill slit and vent
- Tubercle: a small, usually hard excrescence or lump
- Tubiform, Tubuliform: resembling a tube
- Type locality: the location from which the type specimen was collected eg Sydney Harbour
U
- Undulated: waved
- Uniform (as applied to colouration): of one colour
- Urogenital papilla: a papilla through which the urinary waste and gametes leave the body
V
- Vent: the external opening of the alimentary canal, the anus
- Ventral: pertaining to the abdominal or lower surface
- Ventral fins: paired fins behind or below the pectoral fins
- Vertebrae: the bones of the spinal column
- Vertebrate: an animal with a backbone
- Vertical fins: fins on the median line of the body; the dorsal, anal, and caudal fins
- Vestigial: reduced, or very poorly developed
- Villiform teeth: small, slender teeth forming velvety bands
- Viviparous: a species that gives birth to live young. The developing embryo is nourished within the body of the female.
- Vomer: a bone forming the front part of the roof of the mouth
- Vomerine teeth: teeth on the vomer (see above)
X
- xanthism (xanthochroism): An unusual colour variety in which the normal colouration of a fish is largely replaced by yellow pigments. View examples of xanthic Luderick and Sea Mullet.
*Many of the entries in his glossary are taken from McCulloch, 1934 (see below).
Further reading
- Gomon, M.F., Glover, C.J.M. & R.H. Kuiter (Eds). 1994. The Fishes of Australia's South Coast. State Print, Adelaide. Pp. 992.
- Helfman, G.S., Collette, B.B. & D.E. Facey. 1997. The Diversity of Fishes. Blackwell Science. Pp. 528.
- McCulloch, A.R., 1934. The Fishes and Fish-Like Animals of New South Wales. Ed 3. With Supplement by G. P. Whitley. Royal Zoological Society of NSW. pp i-XXvi, 1-104, Pl i-xliii.
- View the Parts of a Fish page.
