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. Then, you notice that a few leaves aren’t performing well. Perhaps they’re turning yellow-brown, having large gaps, or 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. 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

Most often, crypt melt occurs in plants that have just been purchased. Emersed-grown aquariums are plants that have been grown in commercial farms. These plants have the leaves in open air and the roots 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.

To encourage faster growth and reduce algae, plant farms keep their aquatic plants out of water.

An emersed-grown cryptocoryne must be fully submerged before it can become a submerged-grown plant. All the thick, broad, emersed leaves usually melt away, and smaller, thinner, submersed leaves appear in their stead. Aquarium Co-Op is here to help you speed up the conversion process. We give our crypts ample light and inject CO2 before they go on sale. Do not toss your cryptocoryne in the garbage if it begins to melt. You should start to see tiny shoots within weeks, as long as the roots are healthy and it isn’t moved after being planted. You should continue to build submerged-grown leaves once you have seen new growth.

What to do about melted leaves. You should cut off any leaf that is clearly melting near the substrate. 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 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

You can either cut all the leaves to the substrate or trim each one individually to make sure they survive the transition. This last method allows the crypts focus on making new leaf instead of saving the ones that are already there. Keep your aquarium environment stable, and wait several weeks to see whether the cryptocoryne plants return. 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. For algae control and balance, consider adding fast-growing floating plants and stem plants.

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 plant your Cryptocoryne properly in our article here.