How to Identify Short-nosed Tripodfish

To identify Short-nosed Tripodfish (Triacanthus biaculeatus), look at these key features.

Physical Characteristics

Body shape

compressed

Coloration

Generally silvery to yellowish-brown on the dorsal side, fading to silvery-white on the ventral side. Often has indistinct darker blotches or bands on the body. Fins are typically yellowish, sometimes with dusky margins. The caudal fin may have a dark band.

Scale type

none

Mouth position

terminal

Distinctive features

Two prominent, strong, erectile dorsal spines, the first being much longer and thicker than the second., Large, strong pelvic spines that can be locked into an erect position., A relatively short snout, giving it the 'short-nosed' common name., Small, terminal mouth with strong teeth., Rough, sandpaper-like skin due to numerous small, embedded scales.

Dorsal fin

Two dorsal fins; the first with 5-6 strong spines (the first two being very prominent), and the second with 20-26 soft rays. The first spine is significantly longer and thicker than the others.

Tail fin

Slightly forked to truncate caudal fin with 12 rays.

Pectoral fin

Pectoral fins are relatively small, with 13-15 rays.

Distinctive fins

Pelvic fins are reduced to a single, large, strong spine and 1-2 rudimentary soft rays, which can be locked erect and are used for 'tripoding' on the substrate.

Identification Tips

1. 1

   Dorsal Spines

   Look for the two very prominent, strong dorsal spines, especially the first one which is much longer and thicker than the rest. This is a key distinguishing feature from other fish families.

2. 2

   Pelvic Spines

   Observe the large, strong, and erectile pelvic spines. When at rest on the substrate, the fish often uses these, along with the lower caudal fin lobe, to 'tripod'.

3. 3

   Snout Length

   Note the relatively short snout compared to some other tripodfish species, which contributes to its common name.

4. 4

   Body Coloration

   The silvery to yellowish-brown body with potential indistinct darker markings is characteristic.

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