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 appears as naked as a maple leaf in winter. This is common for cryptocorynes. It is sometimes called “crypt melt”.
Crypts (and many other live aquatic plants) are very sensitive to major changes in their water, so they respond by absorbing their existing leaves as they adjust to the different conditions. Crypts can “eat” old leaves to gain energy that allows them to grow new roots and new leaves that can again absorb nutrients and light.
Why is my Crypt Plant dying?
Most often, crypt melt occurs in plants that have just been purchased. Commercial farms often produce emersed-grown aquarium plants, where the leaves are in open air and only the roots are covered in water. Leaves are able to access light and carbon dioxide (CO2) more easily from air versus from water, so this method allows plants to grow faster and larger. Growing the plants out of water also protects the leaves from algae growth, pest snails, and fish diseases.
To encourage faster growth and reduce algae, plant farms keep their aquatic plants out of water.
When you buy an emersed-grown cryptocoryne and put it fully underwater, the crypt must transition into a submersed-grown plant that is accustomed to absorbing light and CO2 from the water. All the thick, broad, emersed leaves usually melt away, and smaller, thinner, submersed leaves appear in their stead. Aquarium Co-Op tries to accelerate this process by providing our crypts with plenty of light and CO2 injection prior to they are sold. If your cryptocoryne starts to melt after it is planted at home, don’t throw it out. As long as it has healthy roots and is not moved once planted, you should see little shoots popping up within a few weeks. Once you see new growth, make sure the crypt has enough lighting and root tab fertilizer to continue building submersed-grown leaves.
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 usually melt first, and then smaller, submersed-grown leaves begin sprouting from the substrate.
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 we have mentioned, crypts can be affected by environmental changes such as shifts in the environment.
– 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
To survive the transition period, you can either prune the leaves one by one as they melt, or you can trim all the leaves 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. Consider adding some fast-growing stem plants and floating plants to help minimize algae growth and keep the tank balanced in the interim.
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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