How to Identify Blunthead Puffer

To identify Blunthead Puffer (Sphoeroides pachygaster), look at these key features.

Physical Characteristics

Body shape

rounded

Coloration

Dorsal surface typically greyish-brown to olive, fading to a lighter, often whitish, ventral side. Some individuals may exhibit faint darker spots or blotches, particularly on the back and sides. Fins are generally translucent or dusky.

Scale type

none

Mouth position

terminal

Distinctive features

Blunt, rounded head, Large eyes, Absence of prominent spines on the body (skin is mostly smooth, though minute prickles may be present on the belly), Small, beak-like mouth with fused teeth, Ability to inflate its body

Dorsal fin

Single dorsal fin, relatively small and set far back on the body, typically with 9-10 soft rays.

Tail fin

Caudal fin is truncate to slightly rounded, often with a dark margin.

Pectoral fin

Pectoral fins are moderately sized, located just behind the gill openings, with 15-17 rays.

Distinctive fins

Pelvic fins are absent. Anal fin is similar in shape and size to the dorsal fin, positioned directly below it, with 8-9 soft rays.

Identification Tips

1. 1

   Body Shape and Spines

   Look for a robust, somewhat inflated body with a blunt head. The key distinguishing feature from many other pufferfish is the largely smooth skin, lacking prominent spines, though minute prickles may be felt on the belly.

2. 2

   Coloration

   Observe the greyish-brown to olive dorsal coloration fading to a lighter belly. Faint darker spots or blotches may be present, but never distinct patterns like stripes or ocelli.

3. 3

   Fin Placement

   Note the small dorsal and anal fins set far back on the body, directly opposite each other. The absence of pelvic fins is also characteristic.

4. 4

   Head and Mouth

   The head is notably blunt and rounded, and the mouth is small and beak-like.

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