The Blackflap/Eared Blenny (Cirripictes auritus) is a peaceful, algae-eating marine fish ideal for maintaining balanced saltwater aquariums. Known for its constant grazing and reef-safe behavior, this hardy species helps naturally control algae growth while adding charm to your tank. With its playful personality and distinctive ear-like fins, the Blackflap Blenny is favored by reef keepers seeking a low-maintenance, eco-friendly solution for algae management. 

Appearance

The Blackflap Blenny has a compact body and expressive eyes, with color variations ranging from reddish-brown to golden hues. Its signature feature is the dark or blue “ear” flaps located on the head, complemented by comb-like teeth for efficient algae grazing. Its short fins and streamlined body allow easy navigation through reef rockwork.

Care & Requirements

Provide live rock with plenty of hiding crevices for natural grazing and territory. Maintain stable water conditions between 72–78°F and a pH of 8.1–8.4. Offer marine-based spirulina, dried seaweed, or blanched greens when natural algae is limited. A secure lid is important, as these fish may jump when startled. House only one per tank unless added simultaneously to large aquariums over 75 gallons.

Can the Blackflap Blenny live in a nano reef tank?
Only if the system holds at least 30 gallons and provides sufficient live rock for grazing.

What should I feed if tank algae runs low?
Supplement with spirulina-based pellets or seaweed sheets several times per week.

Is it aggressive toward other fish?
Generally no, but it may defend its territory from similar-looking blennies.

Tank Mates & Compatibility

This species thrives alongside peaceful community fish such as clownfish, gobies, and wrasses. Avoid large or aggressive species like triggers or dottybacks. It coexists well with corals, invertebrates, and cleanup crew members, contributing to overall tank balance.

Can two Blackflap Blennies share one tank?
Only in tanks over 75 gallons with distinct rock formations for territory.

Is it safe with corals and clams?
Yes, it is reef-safe and does not nip coral polyps or clam mantles.

Will it bother shrimp or snails?
No, these species are compatible and beneficial tank mates.

Aquaculture/Availability

Currently, captive-bred specimens are not consistently available, with most sourced sustainably from wild Indo-Pacific populations. Each fish is health-screened and conditioned for aquarium life to ensure smooth adaptation. Seasonal availability varies with weather and collection conditions.

Are captive-bred Blackflap Blennies available?
Not yet commonly, though aquaculture programs are under development.

Do wild-caught fish adapt well?
Yes, this species is hardy and adjusts quickly to aquariums with ample algae.

Is purchasing wild-caught sustainable?
Yes, when collected under regulated, eco-friendly programs.

FAQ

How large do Blackflap Blennies grow?
Adults typically reach around 4 inches in length, depending on nutrition and habitat space.

Are Blackflap Blennies beginner-friendly?
Yes, they are ideal for beginners due to their peaceful nature and simple dietary needs.

What does a Blackflap Blenny eat?
It feeds on algae and biofilm in the tank; supplement with seaweed or algae-based pellets.

Can it live in a reef tank?
Yes, it is fully reef-safe and helps control algae growth naturally.

How often should it be fed?
Feed small portions 1–2 times daily, ensuring no excess food remains.

Can it jump out of tanks?
Yes, it’s a known jumper, so use a tight-fitting lid.

Does it get along with clownfish or gobies?
Yes, these make ideal companions with no territorial conflict.

What water parameters are best?
Keep salinity between 1.020–1.025 and temperature between 72–78°F.

How long do they live in captivity?
With proper care, most live 4–6 years.

Will it clean algae off aquarium glass?
It primarily grazes on rock and substrate surfaces rather than glass.