Common triplefin

📖 Overview

Facultative air-breathing in the genus ; Adults are most common in shallow water (0-5m), although recorded from depths of 30 m . They are commonly found in intertidal rock pools, particularly those with adequate rocky or algal shelter. They feed mainly on amphipods, isopods, and polychaetes . Eggs are hemispherical and covered with numerous sticky threads that anchor them in the algae on the nesting sites . Larvae are planktonic which occur primarily in shallow, nearshore waters .

🔬 Taxonomy

🐟 Physical Description

Dorsal spines (total): 24 - 31; Dorsal soft rays (total): 11 - 14; Anal spines: 2; Anal soft rays: 23 - 27; Vertebrae: 40 - 45. First dorsal fin spines V-VIII; second dorsal fin spines XIX-XXIII; third dorsal fin rays 11-14. Discontinuous lateral line tubular scales 19-24, notched scales 14-24. Total vertebral number 43-45. Snout profile steep (70-75°). Preoperculo-mandibular canal with 7 pores, 3 at lower corner of preopercular, 3 at tip of upper jaw and 1 at lower jaw symphysis. Scale rows between anterior end of second dorsal fin and lateral line, 5-6. Scales between second and third dorsal fins, 4. Scales around caudal peduncle 12-13. Radii in scales from area below lateral line and under pectoral fin, 8-11. Long ctenii in scales from above and below lateral line in caudal peduncle area. Lateral line canal constricted with W-shaped anterior and posterior openings. Short denticles on interradial circuli. Post-temporal partially exposed. Pterygiophore supporting first segmented ray of third dorsal fin anterior to 24th vertebra. Dorsal fin formula V-0N-0-1-0-1. Ventral edge of lower caudal plate straight. Short neural spine of second preural vertebra. Epurals of different length. Soft rays in caudal fin, 14; 2 unbranched and 5 branched (non multibranched) rays in upper and lower caudal lobes. Procurrent rays in upper caudal lobe, 10; eight in lower lobe, 8; in upper lobe, 2 procurrent rays between upper lobe and posterior epural, 4 rays opposite epurals , 1 between neural spine of second preural vertebra and neural spine of third vertebra, 1 opposite neural spine of third preural vertebra and 2 anterior to neural spine of third vertebra; in lower lobe, one procurrent ray between lower lobe and haemal spine of second preural vertebra, 5 rays opposite haemal spine of second preural vertebra, 1 between haemal spines of second and third preural vertebrae, 1 ray opposite neural spine of third preural vertebra. Rounded posterior end. Short, pointed rostrum. Broad antristrum. Excisura shallow .: elongated.

🌀 Behaviour

The common triplefin is often used for laboratory work on fish physiology and behaviour, as it can remain calm but still active enough to move around and engage with tasks while in experimental conditions. They are also easy to observe in a natural setting due to their lack of skittishness, and so are a popular study species for multiple types of research.

🦐 Diet

The common triplefin shares a similar diet with Yaldwyn's triplefin, the blue-eyed triplefin, the yellow-and-black triplefin, the blue dot triplefin, and the cryptic triplefin, with these species all having a diet consisting mostly of gammarid amphipods, ostracods, limpets, and errant polychaetes. The common triplefin was additionally found to eat a significant amount of caddisflies and sphaeromatid isopods, potentially due to their increased intertidal presence. The feeding behaviour of common triplefins is predatory, with individuals stalking their prey. They will make a brief pause before launching towards it, generally swallowing the animal whole. However, feeding does seem to be largely opportunistic, with individuals usually moving after whichever food is closest to them rather than making the effort to hunt any one specific prey type. The best predictors of dietary preference in New Zealand triplefins are habitat—such as with common triplefins eating species present in intertidal zones—as well as body size. Jaw morphology could explain the body size factor; the common triplefin is a smaller triplefin and as such has a shorter jawbone and tooth length than other, larger triplefin species such as the giant triplefin (twice the size of the common triplefin). This difference in morphology may be preventing them from consuming larger prey items that are more present in the diet of larger fish. In contrast to adults, juveniles spend much less time moving around. Instead of pursuing prey, they will feed on whichever organic matter is near to them, consisting mostly of invertebrates and other particles in the water column. Common triplefin larvae have been found to have significantly more red muscle and smaller white muscles fibres than adults.

🥚 Reproduction

🌍 Habitat & Distribution

Marine; benthopelagic; depth range 0 - 20 m . Temperate Southwest Pacific: throughout New Zealand.

🌿 Ecology

📐 Morphometrics

🌡️ Water Parameters & Tolerance

🛡️ Conservation Assessment

📊 Population Risk & Fisheries

🌐 Names & Taxonomy

🐠 Related Species

🔍 Similar Species

🗺️ Global Occurrence Map

Occurrence records from the Global Biodiversity Information Facility (GBIF) - 1 records indexed .

👥 Community & Contribute