Barnacle Blenny

Aquarium Requirements

Minimum Tank Size: 38–75 litres (10–20 US gallons)

Temperature: 24–27 °C (75–81 °F)

pH: 8.1–8.4

Specific Gravity (Salinity): 1.020–1.025

Alkalinity: 8–12 dKH

Ammonia & Nitrite: 0 ppm

Nitrate:< 10 ppm

Aquascape:
Provide plentiful live rock with small crevices and shells for shelter. Open swimming areas are not required, but hiding spaces are essential. Moderate water flow and stable water parameters are crucial for health.

Diet and Feeding

The Barnacle Blenny is carnivorous, feeding primarily on planktonic and small invertebrate prey in the wild.

Recommended Foods:

• Micro-sized frozen foods (rotifers, baby brine shrimp)

• Finely chopped mysis shrimp and small crustaceans

• Specialized micro-pellets for small blennies

Feed 2–3 times daily in small portions. Juveniles require very small food items to match their tiny mouths.

Temperament and Compatibility

The Barnacle Blenny is peaceful and non-aggressive, making it compatible with most other small, non-aggressive reef fish.

Suitable Tankmates:

• Small gobies, clownfish, dwarf wrasses, and other nano-reef fish

Avoid:

• Large, aggressive, or predatory fish that could consume or stress it

They are highly site-attached, often returning to their chosen shell or crevice after exploring.

Reef Compatibility

✅ Reef Safe

Barnacle Blennies are fully reef safe, posing no threat to corals, sessile invertebrates, or other small reef inhabitants. Their primary role is as a micro-predator of tiny plankton and detritus, contributing to a balanced reef ecosystem.

Additional Information

Maximum Size: 3–4 cm (1–1.5 inches)

Lifespan: 2–4 years in captivity

Difficulty Level: Intermediate (requires micro-food and appropriate habitat)

Natural Behavior: Secretive, crevice-dwelling, planktivore

Origin: Eastern Pacific – Central America to southern Mexico

Coloration: Pale to sandy body with subtle markings, allowing camouflage in shells and crevices

Summary

The Barnacle Blenny (Acanthemblemaria macrospilus) is a tiny, peaceful, reef-safe blenny perfect for nano-reef or small reef aquariums. It requires ample crevices or shells, stable water parameters, and appropriately sized micro-foods. When properly cared for, it exhibits fascinating site-attached behavior, adding both visual interest and functional micro-predation to the reef environment.