Cryptocoryne Aquarium Plants: All About Them (And How to Handle Crypt Melt)

If you're passionate about planted aquariums, you've probably come across the genus Cryptocoryne. More commonly known as 'crypts' among aquarists, these freshwater plants are appreciated for their stunning variety, low-maintenance care, and adaptability. But they also have a well-known quirk: the infamous, and dreaded "crypt melt."

In this post, we'll explore what makes Cryptocoryne species so appealing, which varieties are popular among hobbyists, and what to do if your crypts suddenly seem to disintegrate before your eyes.

What Are Cryptocoryne Plants?

Cryptocoryne is a genus of aquatic plants native to Asia, found in slow-moving rivers, streams, and swamps. There are over 60 recognised species, and they range in appearance from delicate, narrow-leaved varieties to bold, broad-leaf types.

Crypts are rosette-forming plants, meaning their leaves grow in a circular pattern from a central point. They can thrive fully submerged, partially submerged, or even emersed (above water), making them highly versatile.

Popular Cryptocoryne Varieties: 

Here are a few favourites among aquarists:

1. Cryptocoryne wendtii

Cryptocoryne wendtii is one of the most popular and adaptable species of aquarium plants, known for its ease of care and attractive appearance. Native to Sri Lanka, it grows in a rosette form with leaves ranging from 10–25 cm (4–10 inches) tall, making it ideal for the foreground or midground of most tanks. A key feature of C. wendtii is its wide range of colour variants, including green, brown, red, and even tropica or bronze forms—each offering a different tone and texture to an aquascape. It thrives in low to moderate light, does well without CO₂, and adapts to a variety of water conditions. Interestingly it can actually be used as a epiphyte meaning it can be attached to wood or rock. 

2. Cryptocoryne parva

Cryptocoryne parva is one of the smallest and slowest-growing species in the Cryptocoryne genus, making it an excellent choice for the foreground of freshwater aquariums. Native to Sri Lanka, it features short, narrow, grass-like leaves that typically grow only 3–10 cm (1–4 inches) tall. Unlike many other Crypts, C. parva retains its bright green coloration under most lighting conditions and does not change shape significantly when transitioning from emersed to submerged growth. It thrives in moderate light, but due to its slow growth, it benefits from CO₂ supplementation and a nutrient-rich substrate. While it doesn't spread quickly, its compact size and neat appearance make it perfect for creating a low, grassy carpet in aquascapes.

3. Cryptocoryne balansae

Cryptocoryne balansae is a tall, elegant aquatic plant native to Thailand, popular in larger freshwater aquariums. It features long, narrow, sword-like leaves that can reach 30–60 cm (12–24 inches) in height, often with attractive ruffled edges and a deep green to bronze coloration. This plant prefers moderate to high lighting and benefits from a nutrient-rich substrate and added CO₂, though it can adapt to low-tech setups. Due to its height, it's best used in the background of aquascapes, where it can create a lush, jungle-like appearance.

4. Cryptocoryne undulata (also known as axelrodi)

Known for its slightly wavy, reddish-brown leaves, C.undulata adds texture and warmth to an aquascape and it features slender, wavy-edged leaves that range in colour from green to reddish-brown, depending on lighting and substrate. Cryptocoryne undulata typically grows to a height of 10–30 cm (4–12 inches) and spreads about 5–15 cm (2–6 inches) wide, depending on tank conditions and lighting. This makes it suitable for the midground in small tanks or foreground to midground in larger aquariums.

5. Cryptocoryne spiralis Red & Tiger

Cryptocoryne spiralis comes in striking variations like Red and Tiger, both prized for their dramatic leaves. The Red variety boasts deep reddish-brown foliage with a lime green stripe that adds vibrant colour and contrast, while the Tiger variant features bold striped patterns on its leaves, resembling a tiger’s stripes, also with a lime green stripe. Both types grow tall, making them excellent midground or background plants that bring texture and visual interest to any aquascape. 

Why Choose Crypts for Your Aquarium?

• Low Light Tolerance: Crypts do well in moderate to low light conditions, making them perfect for low-tech setups.

• Minimal CO₂ Requirements: While CO₂ injection can enhance growth and colouration, most crypts don’t need it to thrive.

• Root Feeders: They prefer to draw nutrients from the substrate, so using root tabs or a nutrient-rich base can boost growth.

• Great for Aquascaping: Their varied sizes and colours make them versatile choices for every layer of your tank.

Understanding “Crypt Melt”

Despite their hardiness, crypts have a notorious tendency to suddenly lose their leaves—a phenomenon known as crypt melt.

What Is Crypt Melt?

Crypt melt occurs when a plant rapidly sheds its leaves, often within days of being introduced to a new tank. This can be alarming, but it’s not always fatal.

Common Causes of Crypt Melt:

• Change in Water Parameters: Crypts are sensitive to sudden changes in pH, temperature, or hardness.

• Transplant Shock: Moving the plant from one tank to another or from an emersed (above-water) to submerged (underwater) environment often triggers melt.

• Lighting Changes: A drastic increase or decrease in light intensity can stress the plant.

• Nutrient Deficiency: Poor substrate or lack of root tabs may lead to unhealthy roots and leaf loss.

What To Do When It Happens:

1. Don’t Panic: Crypt melt looks dramatic, but the roots often survive.

2. Leave the Roots Alone: Resist the urge to pull up the plant. As long as the roots are healthy, new leaves will sprout.

3. Trim Dead Leaves: Remove mushy or decaying foliage to prevent ammonia spikes.

4. Stabilise Tank Conditions: Maintain consistent water parameters and avoid further changes for a few weeks.

5. Add Root Tabs: Feeding the roots directly can speed up recovery.

6. Use Seachem Flourish Advance: This natural phytohormone boosts root development and in our experience helps crypts bounce back faster after melting.

Many aquarists report that after melting, crypts come back even stronger and more adapted to their new environment and often producing more vibrant foliage.

Final Thoughts

Cryptocoryne species are a must in the aquascaping world for good reason. They're beautiful, adaptable, and perfect for tanks of all sizes and experience levels. While crypt melt can be unsettling, it’s usually a temporary setback. With patience and proper care, your crypts will bounce back and thrive.

Whether you're building a lush jungle-style tank or adding subtle greenery to a minimalist aquascape, crypts are a fantastic addition. Just remember: when your crypts melt, don’t give up it's all part of the journey.