All fish / Platyrhinidae

Thornback Guitarfish

Platyrhinoidis triseriata

Also known as thornback ray, california thornback, thornback, banjo ray, thornback guitar fish

A flattened, rounded-disc ray with a long thick tail, two dorsal fins and three rows of hooked thorns running down the back and tail. It is olive to grey-brown above and pale beneath. Public aquariums and a few specialist keepers keep it for its calm nature and interesting bottom-dwelling behaviour.

Care at a glance

Care level

Hard

Temperament

Peaceful

Adult size

60 cm

Temperature

12 to 20 °C

pH

8 to 8.4

Smallest tank

2000 litres

Keep as

Singly or in small groups in a very large system

Diet

Carnivore: shrimp, squid, clams, worms and small fish

Swims

Bottom of the tank

Lifespan

10 to 15 years

Water

Marine (saltwater)

Wild range

Eastern Pacific: central California, USA to Baja California, Mexico

Breeding

It is a live bearer that gives birth to a small litter of fully formed pups in late summer. Captive breeding has happened in public aquariums but is rare in home systems.

Good to know

This is a coldwater species that grows to around 90 cm in total length and needs a huge, chilled tank with a wide sandy floor, so it is unsuitable for most home aquariums. Handle with care because of its thorns, and keep it away from fish small enough to eat.