QUICK STATS

Care Level: Easy to Moderate
Diet: Omnivore / Herbivore-Leaning
Temperament: Peaceful to Mildly Territorial
Reef-Safe: Yes, With Caution
Venomous/Toxic: No
Approximate Purchase Size: 1-2"
Approximate Max Size: Around 3-4"
Recommended Tank Size: 20-30 Gallons or Larger

FLAMETAIL BLENNY

The Flametail Blenny (Enchelyurus flavipes), also called the Yellowtail Black Blenny, is a small reef-safe blenny known for its dark body and bright yellow to orange tail and fin coloration. It is sometimes confused with the Bicolor Blenny, but the true Flametail Blenny has a darker body, yellow posterior fins, a more rounded head, and a different overall shape. Because apparently even tiny perch fish needed a naming dispute.

Flametail Blennies are active, curious, and full of personality. They often perch on rockwork, hop across the aquascape, and wedge themselves into small crevices when resting or startled. Like many blennies, they do not swim constantly in open water, but they still move around the aquarium frequently while grazing, exploring, and acting like they own several square inches of reef real estate.

This species is generally considered reef-safe and should not bother most corals or invertebrates. However, like many algae-grazing blennies, it may occasionally nip at coral tissue, fleshy polyps, clam mantles, or other surfaces if underfed or if it develops bad habits. So yes, reef-safe, but with the usual blenny fine print. Nature remains committed to loopholes.

Note: Image is a representation of what to expect. The fish you receive may vary slightly in size, color, markings, and overall appearance.

AQUARIUM REQUIREMENTS

AQUARIUM SIZE

A minimum tank size of 20 gallons or larger is recommended for a Flametail Blenny, though 30 gallons or larger is preferred for better stability, more grazing surfaces, and more room for tank mates.

While this fish stays relatively small, it still benefits from an established aquarium with live rock and natural grazing opportunities. Larger aquariums also help reduce territorial behavior, especially if housing other bottom-dwelling or rock-perching fish.

HABITAT RECOMMENDATIONS

Flametail Blennies do best in established aquariums with live rock, hiding places, and plenty of surfaces for grazing and perching.

Aquascaping: Provide live rock, caves, crevices, ledges, and open areas for movement. Blennies enjoy perching and darting between hiding spots like tiny reef gremlins with scheduling conflicts.

Substrate: Sand, fine aragonite, crushed coral, or bare-bottom systems can work. This species does not depend heavily on the sandbed.

Rockwork: Live rock is strongly recommended. It provides shelter, territory, natural grazing surfaces, and biological filtration.

Tank Maturity: A mature aquarium is preferred. Established rockwork with film algae and biofilm gives the blenny natural grazing opportunities throughout the day.

Tank Cover: A tight-fitting lid is recommended. Blennies can jump, because apparently no fish has ever looked at an open top and made a responsible choice.

WATER PARAMETERS

Flametail Blennies are generally hardy once established, but they still need clean, stable marine conditions. “Hardy” means forgiving, not indestructible, despite the hobby’s ongoing attempt to confuse those two words.

Temperature: 72-78°F
pH Level: 8.1-8.4
Salinity: 1.020-1.026 specific gravity
Ammonia, Nitrite, and Nitrate: Ammonia and nitrite should remain undetectable. Nitrate should be kept as low as reasonably possible, ideally below 20 ppm.
Water Flow: Low to moderate flow is ideal. Provide enough movement to keep the aquarium oxygenated and move waste toward filtration, while still allowing calmer areas for resting and perching.

DIET

Flametail Blennies are omnivores with a herbivore-leaning diet. They naturally graze on film algae, biofilm, and small organisms found on rock surfaces, but they should also be offered a varied aquarium diet.

PRIMARY DIET

Frozen Food: Offer algae-rich frozen blends, mysis shrimp, enriched brine shrimp, marine blends, and other small frozen foods. We at Summit City Coral prefer frozen foods such as LRS Herbivore Frenzy and PE Mysis.

Prepared Herbivore Foods: High-quality herbivore pellets, spirulina flakes, marine algae pellets, and omnivore blends can help provide balanced nutrition.

Algae-Based Foods: Nori, seaweed sheets, spirulina, algae wafers, and herbivore blends can be offered regularly. Some individuals may take to seaweed quickly, while others may need time to realize the green rectangle is food and not aquarium furniture.

Natural Grazing: Established live rock with film algae and biofilm can help support natural feeding behavior. This should be viewed as supplemental, not the entire feeding plan. A blenny is not a free algae-control subscription.

FEEDING FREQUENCY

Feed small amounts 1-2 times per day, with algae-based foods offered regularly. Watch body condition closely, especially in newer or very clean aquariums where natural grazing may be limited.

COMPATIBILITY

Flametail Blennies are generally peaceful, but they may become territorial toward similar-shaped fish, especially other blennies. They work best in peaceful to semi-peaceful reef aquariums with plenty of rockwork and hiding areas.

COMMON TANK MATES

Fish: Clownfish, cardinalfish, firefish, gobies, peaceful wrasses, chromis, dwarf angelfish, tangs in larger aquariums, and other peaceful community fish.

Avoid: Other blennies in smaller aquariums, aggressive dottybacks, aggressive damsels, large predatory fish, triggers, groupers, lionfish, and fish likely to bully or eat them.

Same Species: Best kept singly unless the aquarium is large enough and the fish are a bonded pair. Multiple similar blennies may fight over territory.

Invertebrates: Usually safe with cleaner shrimp, hermit crabs, snails, urchins, and most common reef invertebrates.

Coral: Flametail Blennies are generally considered reef-safe with caution. They usually ignore soft corals, LPS, SPS, zoanthids, mushrooms, and anemones, but occasional nipping can happen, especially if the fish is underfed or develops a taste for coral mucus or clam mantles.

BEHAVIORAL NOTES

Temperament: Peaceful to mildly territorial. May defend a favorite cave, perch, or section of rockwork.

Perching Behavior: Frequently rests on rocks, ledges, and aquarium surfaces. Blennies often appear to “hop” around because they lack the same open-water swimming style as many other fish.

Grazing Behavior: Spends time picking at algae, biofilm, and tiny foods on rock surfaces.

Reef Compatibility: Good for most reef tanks, but best listed as reef-safe with caution due to the small possibility of coral or clam mantle nipping.

Territoriality: May show aggression toward other blennies, gobies, or similarly shaped fish in smaller aquariums.

Coloration: Typically has a dark body with bright yellow to orange coloration on the tail and rear fins, giving it the “flametail” look.

Difference From Bicolor Blenny: Flametail Blennies are often confused with Bicolor Blennies, but the true Flametail Blenny is typically darker overall with yellow tail/rear fin coloration and a different head shape.

Feeding Risk: Very clean tanks may not provide enough natural grazing. Offer regular algae-based and prepared foods to keep the fish healthy.

Jumping: A tight-fitting lid is recommended. Small blennies can and will make theatrical little mistakes if given the opportunity.

ACCLIMATION PROCESS

This acclimation method helps reduce stress by gradually introducing the fish to your aquarium’s temperature and water chemistry.

1. TURN OFF THE LIGHTS & ATO

Turn off aquarium lights to reduce stress. If you have an Auto Top Off system, switch it off before starting acclimation.

2. FLOAT THE BAG

Float the sealed bag in the aquarium for 15-20 minutes to allow the temperature in the bag to equalize with the tank.

3. OPEN BAG, ADD FISH TO CONTAINER

Carefully open the bag and transfer the fish and shipping water into a clean bucket or container.

4. ACCLIMATE USING TANK WATER

Add 1/4 cup of tank water to the container every 5 minutes for 40 minutes.

5. TRANSFER FISH TO AQUARIUM

Once acclimation is complete, gently transfer the fish into the aquarium using a net or specimen container. Discard the shipping water. Do not pour shipping water into your aquarium.

6. REFILL THE AQUARIUM WITH SALTWATER

You may need to replace the saltwater removed during acclimation with fresh mixed saltwater.