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Two Spot Blenny
Ecsenius bimaculatus
The Two Spot Blenny is one of the tiniest Ecsenius blennies available — a compact, nano-friendly algae grazer with twin distinctive black eye-spots and a cheerful personality that fills small reef tanks with movement and character.
Quick Care Overview
| Scientific Name | Ecsenius bimaculatus |
|---|---|
| Temperament | Semi-aggressive |
| Reef Safe | ✅ Yes |
| Minimum Tank Size | 10–15 gallons |
| Diet | Herbivore — microalgae, nori, spirulina |
| Care Level | Easy |
| Adult Size | 2.5–3 inches (6–7 cm) |
Why the Two Spot Blenny Is So Popular
At $21.99 the Two Spot Blenny is one of the most affordable blennies in the hobby, and its nano-compatible adult size makes it accessible to hobbyists with smaller systems who can’t keep most blennies. Despite its small size, it has a big personality and is constantly visible — perching, grazing, and peering at its surroundings with large expressive eyes.
Best Tank Setup
Works in nano reefs as small as 10–15 gallons, though 20 gallons or more is ideal for stable water parameters. Provide live rock with microalgae growth, crevices for shelter, and a nori clip for supplemental feeding. A mature tank with established growth gives this fish its best start.
Feeding Guide
Clip nori sheets and offer spirulina flakes and algae pellets. In mature tanks with microalgae growth, it grazes continuously. In clean nano tanks, supplement every day without fail — at 2.5 inches it has a fast metabolism and needs consistent food access.
Compatibility
Semi-aggressive toward similar blennies — keep only one per tank in most setups. Compatible with nano-appropriate reef fish: clownfish, small gobies, cardinalfish. Safe with all corals and invertebrates.
Common Mistakes
Insufficient algae: Small nano tanks deplete algae quickly — supplement daily. Pairing with similar blennies: Even in nano tanks, territorial conflicts occur. Overlooking this species: At under $22, it’s often dismissed as an entry-level fish — but it’s genuinely delightful and long-lived when cared for properly.
Is This Fish Right for Your Aquarium?
The Two Spot Blenny is perfect for nano reef keepers who want a characterful, reef-safe algae grazer that fits comfortably in smaller systems. Outstanding value at $21.99.
🔗 Browse all blennies · All saltwater fish · Reef-safe fish guide
Ready to Add the Two Spot Blenny to Your Reef?
Frequently Asked Questions
Is the Two Spot Blenny reef safe?
Yes — grazes microalgae and will not harm corals or invertebrates.
What does it eat?
Primarily herbivorous — microalgae, nori, spirulina flakes, and algae-based pellets.
How big does it get?
Adults reach approximately 2.5–3 inches (6–7 cm) — one of the better options for nano reef tanks.
Is it good for nano tanks?
Yes — suitable for tanks as small as 10–15 gallons, though 20 gallons or more is preferred.
What are the two spots?
The distinctive twin black spots near the dorsal fin base are the species’ namesake markings, visible even on juveniles.