All fish / Blenniidae

Molly Miller blenny

Scartella cristata

Also known as molly miller, molly miller blenny, crested blenny, hairy blenny, mollie miller

A sturdy rock-dwelling blenny with a blunt head, a crest of small cirri on top of the head and a mottled olive, brown and pale body. Aquarists keep it because it grazes hair algae hard and has a bold, characterful habit of perching on rocks and watching the room.

Care at a glance

Care level

Easy

Temperament

Semi

Adult size

10 cm

Temperature

22 to 27 °C

pH

8.1 to 8.4

Smallest tank

110 litres

Keep as

Singly, or one per tank unless the tank is large

Diet

Herbivore: grazes filamentous algae, plus nori, spirulina-based flakes and pellets, with some mysis and brine shrimp

Swims

Bottom of the tank

Lifespan

3 to 5 years

Water

Marine (saltwater)

Wild range

Tropical and subtropical Atlantic, including the Caribbean, Gulf of Mexico, Mediterranean and West Africa

Breeding

Males guard eggs laid on the ceiling of a rock crevice or shell until they hatch. Spawning sometimes happens in aquariums, but the tiny pelagic larvae are very hard to rear and captive breeding is rare.

Good to know

It can become territorial towards other blennies and similar bottom-dwelling fish, and it may nip at some corals or clam mantles once algae runs short. Keep a tight lid because it can jump.