Nannostomus Mortenthaleri

The Coral Red Pencilfish, scientifically known as Nannostomus Mortenthaleri, is a compact whirlwind of color that brings a refined pop of red to any freshwater setup. Its slender, pencil-thin silhouette glides through the water with an effortless grace, making it a standout in planted tanks or nano aquariums.

Why this fish matters in your aquarium:

• Vibrant coral-red coloration that shines under natural and LED lighting, especially when fed a varied diet and kept in stable, clean water.
• Peaceful, schooling nature—group them in 6 or more to see dynamic, coordinated swirls that create a living focal point in your tank.
• Ideal for planted and nano setups thanks to their small size, unobtrusive presence, and love of slow-flow environments with plenty of hiding spots among plants and wood.
• Low to moderate maintenance when water is stable. They prefer soft, well-filtered water and a gently dimmed day-night cycle that reduces stress and brings out their colors.
• Active yet non-aggressive tank mates—great with other small, peaceful species that won’t nip fins or outcompete food, making them a versatile addition to community tanks.

Care at a glance

habitat: warm, freshwater aquariums with ample plant cover and gentle filtration

water: soft to moderately soft conditions with a slightly acidic to neutral pH range

temperature: comfortable for most tropical setups

diet: small live or frozen foods (such as micro-worms or nauplii), supplemented with high-quality micro pellets and flakes

What this means for you

If you’re building a visually striking, tranquil community tank, the Nannostomus Mortenthaleri offers a reliable centerpiece without overpowering the ecosystem. It rewards careful aquarists who maintain stable water parameters and provide plenty of plant drama for them to weave through. Expect a lively display as they school in synchronized patterns, showing off the Coral Red Pencilfish’s most distinctive trait: a rich, eye-catching red that remains true with proper care.

Ideal scenarios and use cases

• Planted tanks where subtle movement and color are the main attraction
• Nano aquariums seeking a peaceful, visually engaging schooling species
• Community setups with small, non-aggressive inhabitants that share similar water needs

In short, the Nannostomus Mortenthaleri is a deliberate, color-forward choice for aquarists who value harmony, color, and a touch of elegance in their freshwater landscape. The Coral Red Pencilfish isn’t just a pretty face—it’s a reliable performer that adds depth, movement, and conversation to your hobby.