Why is my Cryptocoryne plant melting?

You just planted your new cryptocoryne (or crypt) plant in the aquarium, and it looks perfect for the first few days. Then you notice that one or two leaves aren’t doing so well. Maybe they are turning yellow-brown, have large gaping holes, or are simply withering away. Soon, the entire plant will look as barren as a maple tree in winter. This phenomenon is very common with cryptocorynes and is often called “crypt melt.”

Crypts and many other aquatic plants are extremely sensitive to changes in water quality. As such, they absorb the existing leaves to adjust to changing conditions. The energy they gain from “consuming” the old leaves allows the crypts to create new roots and leaves that can once again gather nutrients and light in their new environment.

Why is my new Crypt plant dying?

Crypt melt most frequently occurs in newly purchased plants. Commercial farms often produce emersed-grown aquarium plants, where the leaves are in open air and only the roots are covered in water. This allows the plants to grow faster and more quickly because they can access light and carbon dioxide (CO2) from air better than from water. Growing the plants out of water also protects the leaves from algae growth, pest snails, and fish diseases.

Aquatic farms grow aquatic plants without water in order to promote faster growth and minimize algae.

If you purchase an emersed-grown Cryptocoryne, and then put it completely underwater, the crypt will transform into a submerged-grown plant that is used to absorbing light CO2 from water. The emersed leaves are usually large and broad. Submerged leaves are smaller and more delicate. Aquarium Co-Op helps to speed up this process by giving our crypts lots of light and CO2 infusion 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. You should start to see tiny shoots within weeks, as long as the roots are healthy and it isn’t moved after being planted. Once you see new growth, make sure the crypt has enough lighting and root tab fertilizer to continue building submersed-grown leaves.

What to do with melted leaves. 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.

Larger, emersed-grown leaf usually melts first, then smaller, submerged-grown leaves start 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 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

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. Keep the aquarium environment as stable as possible, and wait for several weeks to see if the cryptocoryne plants come back. 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.

You can find out how to properly plant your Cryptocoryne here.

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