Why is My Cryptocoryne Pot Melting?
You just planted your new cryptocoryne (or crypt) plant in the aquarium, and it looks perfect for the first few days. You notice that one or two of the leaves isn’t growing well. They might be turning yellow-brown or have large, gaping holes or simply withering away. Soon the whole plant looks as bare as a maple tree in winter. This is a common phenomenon with cryptocorynes, and it is often called “crypt melting.”
Crypts, like many aquatic plants, are sensitive to water changes. They absorb their leaves as they adapt to new conditions. They “eat” the old leaves, which gives them energy to make new roots and create new leaves that can absorb nutrients and light.
Why is my Crypt Plant dying?
Crypt melt most frequently occurs in newly purchased plants. Emersed-grown aquarium plants are often grown in commercial farms. The leaves are exposed to the air while the roots are kept in water. Because leaves can access light and carbon dioxide (CO2) easier from air than water, this allows them to grow faster. Growing the plants out of water also protects the leaves from algae growth, pest snails, and fish diseases.
Plant farms grow their aquatic plants with the leaves out of water to encourage faster growth and minimize algae.
An emersed-grown cryptocoryne must be fully submerged before it can become a submerged-grown plant. All the thick, broad, emersed crypt leaves eventually fall away and submerged, smaller leaves take their place. At Aquarium Co-Op, we try to jumpstart this conversion process for you by giving our crypts plenty of light and CO2 injection before they are sold. However, if you see your cryptocoryne melting after you plant it at home, do not throw it away in the trash. As long as it has healthy roots and is not moved once planted, you should see little shoots popping up within a few weeks. If you notice new growth, ensure the crypt has sufficient lighting and root tab fertilizer so that it can continue to grow submerged-grown foliage.
What can I do about melted leaves? Cut off the leaf at the base near the substrate if you notice it is melting. Rotting leaves can sometimes cause nitrogen spikes or algae growth, so it’s best to remove them unless your clean-up crew members consume the dead leaf first.
The larger, emersed grown leaves tend to melt first and then the smaller, submerged-grown plants start sprouting.
Why Are My Established Crypts Melting?
Sometimes cryptocoryne plants may experience melting seemingly randomly, despite growing well in your fish tank for many months. As mentioned previously, crypts are very susceptible to environmental changes, such as shifts in:
– Water quality – Water change frequency – Location (e.g., moving the crypt) – Lighting – Fertilizer dosing – Temperature during hot summers – CO2 injection – Fish food – Pollutants in the air
You have two options to survive the transition period: you can either trim the leaves individually as they melt or you can trim them all back to the substrate. This allows the crypt to concentrate on creating new leaves and not trying to save old ones. You should keep the aquarium environment as stable and allow the plants to grow back for several weeks. Also, remember that while the crypts are melting or pruned back, your fish tank is more prone to an algae bloom because the crypts are no longer consuming as many nutrients in the water. You can add floating and fast-growing plants as well as stem plants to reduce algae growth.
Do not immediately throw away a melted crypt, but rather wait at least three to four weeks to see if the plant will recover and send out new shoots.
To learn how to properly plant your cryptocoryne, read our article on the different techniques here:
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