Fish, Tanks and Ponds

Fish, Tanks and Ponds
A comprehensive guide to fish

Ciliata mustela

Five bearded rockling

Five bearded rockling, Ciliata mustelaFive bearded rockling, Ciliata mustela
Photos by Michelle Stuart & Andy Rapson


Ciliata: Latin, cilium = eye lid, eye lash

General Notes:

C. mustela is a little more sensitive about water quality than most other rock pool fish and the species is quite shy in general which means that this fish may take a little time to fully settle in before it starts eating properly.

Use a spacious aquarium with subdued lighting, a sandy substrate and lots of rock work and weeds to create hiding places. At low tide C. mustela can often be found under stones or in thick sea weed in rock pools at the lower part of the intertidal zone.

Long term C. mustela will tolerate temperatures up to 24°C  (75°F) although they will tolerate higher temps for a short while. In most cases a cooler will not be required.


Generally peaceful but will prey on fish small enough to eat. Prone to panic if startled and may injure itself when dashing around so a group of dither fish such as a group of small mullet will help to prevent this.

Food and feeding:

In the wild C. mustela feeds mainly on crustaceans, sometimes also on algae, polychaetes, gastropods and occasionally, small fish. In captivity once the fish has settled down it will accept a range of live or frozen invertebrates such as mysis shrimps, brine shrimps, krill, chopped squid, chopped shell fish and some vegetable matter. All are obtainable from most pet fish shops which normally carry a range of sterilised and frozen food for marine fish.


There are no external differences between the genders other than adult females are larger than the males.


Unknown in the aquarium. C. mustela breeds in winter - spring in deeper water off shore. The Eggs and larvae are pelagic.

Wild status:

The IUCN Red List of Endangered Species hasn't evaluated C. mustela. But it has a wide range and is common throughout most of its range and isn't facing any immediate threats.

Further Information:

There are several other species of rockling which are similar in appearance but can be differentiated by the number of barbels on the head.

Information at a glance

pH: 8.2 - 8.4
dGH: 8 - 12
Salinity: 1.021 - 1.025
Temperature: 8 - 24°C (46 - 75°F)
Diet: Omnivore
Size: 20cm (8in)
Min tank size: 250 litres
Difficulty level: Intermediate
Aquarium type: Community
Swimming level: Bottom

Distribution and habitat

distribution map for Helostoma temminckii

Origin: Northeast Atlantic: Lisbon north to Finnmark, around the British Isles, in the Skagerrak and Kattegat and Iceland

Habitat: A resident intertidal species with homing behaviour. Generally close to the shore, not descending to great depths beyond the limits of the distribution of green algae (20 m), preferring rock bottoms but also living on sandy, muddy, and shell gravel bottoms


Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Gadiformes
Family: Lotidae
Genus: Ciliata
Species: C. mustela, (Linnaeus, 1758)

Gadus mustela,
Enchelyopus mustela,
Gaidropsarus mustela,
Motella mustela,
Onos mustela,
Ciliata glauca,
Couchia glauca,
Couchia minor,
Motella argenteola,
Molvella borealis