This species was first described in 1814 by the English zoologist William Elford Leach who named it Caprella penantis in honour of the Welsh naturalist Thomas Pennant.

[2] Like other caprellid skeleton shrimps, Caprella penantis has a cylindrical, slender body with much reduced abdominal segments.

The gnathopods (feeding appendages) are hooked and the three pairs of pereiopods (walking legs) are modified for clinging on to the plants and other organisms amongst which it lives.

Compared to other caprellids in similar habitats, it has a small, sharply-pointed rostrum on its head and a relatively robust body.

[3] Caprella penantis has a cosmopolitan distribution, being present in tropical, subtropical and temperate seas worldwide.