Blennies are among the most entertaining and practical additions to any reef aquarium. These small, personable fish are known for their curious behavior, unique perching habits, and—in many species—their appetite for nuisance algae. Whether you're looking for a helpful clean-up crew member or simply a fish with character, there's a blenny for every tank.
Why Blennies Make Great Reef Tank Fish
Blennies offer a unique combination of personality and practicality that makes them favorites among reef keepers:
- Reef-Safe: Most blennies won't bother corals or other invertebrates
- Algae Control: Many species graze constantly on nuisance algae
- Entertaining: Their quirky perching behavior and curious nature make them fun to watch
- Hardy: Generally robust fish that adapt well to aquarium life
- Nano-Friendly: Many species thrive in smaller tanks
Best Blenny Species for Reef Tanks
Midas Blenny (Ecsenius midas)
The Midas Blenny is often considered the crown jewel of reef-safe blennies. Its stunning golden-yellow coloration and active swimming pattern set it apart from other blenny species. Unlike many blennies that perch on rocks, the Midas Blenny often hovers in the water column, mimicking the behavior of anthias.
- Max Size: 5 inches
- Min Tank: 30 gallons
- Temperament: Generally peaceful, but can be territorial with similar-looking fish
- Diet: Omnivore - accepts frozen and prepared foods readily
Tailspot Blenny (Ecsenius stigmatura)
The Tailspot Blenny is a popular choice for nano reef tanks. Named for the distinctive dark spot at the base of its tail, this small blenny has big personality. It's an excellent algae grazer and peaceful community fish.
- Max Size: 2.5 inches
- Min Tank: 10 gallons
- Temperament: Very peaceful
- Diet: Primarily herbivorous, loves to graze on hair algae
Bicolor Blenny (Ecsenius bicolor)
The Bicolor Blenny features a striking two-tone pattern with a dark front half and orange-brown rear. This species is an enthusiastic algae eater and will work tirelessly to keep your rocks clean.
- Max Size: 4 inches
- Min Tank: 30 gallons
- Temperament: Can be feisty with other blennies
- Diet: Herbivore - needs algae-based foods and grazing opportunities
Starry Blenny (Salarias ramosus)
The Starry Blenny is a powerhouse algae eater. With its mottled brown coloration covered in white spots, it may not be the most colorful blenny, but it's arguably the most effective at controlling hair algae and film algae.
- Max Size: 5.5 inches
- Min Tank: 40 gallons
- Temperament: Territorial with other herbivorous fish
- Diet: Strict herbivore - requires lots of algae growth or supplementation
Lawnmower Blenny (Salarias fasciatus)
The Lawnmower Blenny lives up to its name as one of the best algae-eating fish available. Its comical appearance and constant grazing behavior make it a reef tank classic.
- Max Size: 5 inches
- Min Tank: 40 gallons
- Temperament: Peaceful but needs room to graze
- Diet: Herbivore - may require nori or algae sheets if tank is too clean
Tank Requirements for Blennies
Water Parameters
Blennies are generally hardy but still require stable reef-quality water:
- Temperature: 74-82°F (ideal: 76-78°F)
- Salinity: 1.023-1.026 SG
- pH: 8.1-8.4
- Ammonia/Nitrite: 0 ppm
- Nitrate: Below 20 ppm
Track your parameters regularly with the ReefBay app to catch any trends before they become problems.
Aquascaping
Blennies are perching fish that need appropriate rock structure:
- Provide plenty of live rock with holes and crevices
- Create multiple hiding spots and perching areas
- Ensure rock surfaces for herbivorous species to graze
- Consider adding PVC tubes or ceramic caves for additional cover
Feeding Your Blenny
Feeding requirements vary significantly between blenny species:
Herbivorous Blennies (Tailspot, Bicolor, Starry, Lawnmower)
- Primary diet should be algae-based foods
- Offer nori sheets or algae clips daily
- Supplement with spirulina-enriched pellets or flakes
- Ensure adequate algae growth in the tank or feed more heavily
Omnivorous Blennies (Midas)
- Accept a wider variety of foods
- Offer high-quality pellets, frozen mysis, and brine shrimp
- Include some vegetable matter in their diet
- Feed 2-3 times daily in small amounts
Common Health Issues
Starvation in Algae-Eating Species
The most common problem with herbivorous blennies is starvation. In a very clean tank with minimal algae growth, these fish can slowly starve despite accepting prepared foods. Signs include:
- Sunken belly
- Decreased activity
- Faded coloration
Prevention: Supplement heavily with nori, algae sheets, and spirulina-based foods. Consider growing chaeto or macroalgae in a refugium to provide natural grazing material.
Jumping
Blennies are notorious jumpers, especially when first introduced or stressed. Always use a tight-fitting lid or mesh screen top to prevent escape.
Ich and Marine Velvet
Like all marine fish, blennies can be susceptible to parasitic infections. Quarantine new arrivals for 4-6 weeks before adding to your display tank.
Tank Mates
Most blennies are peaceful community fish that coexist well with other reef inhabitants:
- Compatible: Clownfish, gobies, wrasses, cardinalfish, anthias
- Use Caution: Other blennies (territorial conflicts), similar-looking fish
- Avoid: Large aggressive fish that may bully them
Important: Generally keep only one blenny per tank unless the tank is very large (100+ gallons) with distinct territories. Multiple blennies often fight.
Tips for Success
- Choose the right species for your tank size - Don't put a lawnmower blenny in a 20-gallon nano
- Have a backup food plan - Even algae eaters need supplemental feeding
- Secure your tank - Use a lid or screen top to prevent jumping
- Quarantine - Always QT new arrivals to prevent disease introduction
- One per tank - Avoid blenny-on-blenny aggression with single specimens
Where to Buy Blennies
Browse our selection of blennies from verified ReefBay sellers. We connect you with reputable hobbyists and shops offering healthy, tank-raised specimens whenever possible.
Conclusion
Blennies are fantastic reef tank additions that offer personality, practicality, and endless entertainment. Whether you choose a stunning Midas Blenny or a hardworking Lawnmower Blenny, these fish will quickly become favorites in your aquarium. With proper care, feeding, and an appropriate environment, your blenny will thrive for years.
Ready to add a blenny to your reef? Browse blennies on ReefBay or track your tank parameters with the ReefBay app to ensure your tank is ready for its newest resident.
