The Small Red-eyed Damselfy is a small damselfly, about 29 millimetres long, predominantly black with iridescent blue markings.
Its large, spaced eyes are a deep red.

The Small Red-eyed Damselfy is very similar to the Red-eyed Damselfly (Erythromma najas) but smaller and more slender.
Like the Red-eyed Damselfly, both sexes lack pale spots behind the eyes and have pale brown pterostigmata.
The male has a bronze-black top and blue sides.
Viewed from the side, the second and eighth segment of the abdomen of the male are mostly blue, which distinguishes it from the Red-eyed Damselfly where these are mostly black.
The sides of the female's thorax are yellow, green or blue.
The female has complete, thin green or blue ante-humeral lines.
The rear edge of the pronotum is rounded.

This is a recently born female.

Boekel area, The Netherlands, 6 July 2018