Crypt melt is a little understood phenomenon in which crypts develop holes in their leaves and then begin to disintegrate, leaf by leaf. Many a beginner hobbyist has purchased a crypt, only to watch it wither away within a couple of weeks. This usually results in the hobbyist avoiding crypts all together from that point onwards. However, for those who take the time to understand crypts and the reasons for the infamous crypt melt, success with these plants is within easy reach.
Reasons for Crypt Melt
The reasons for crypts melting can be summarised in one word; change. The immediate response of all crypts to any sort of change is to melt. While the reasons for this are unclear, there are a couple of plausible theories. One theory suggests that it is a defence mechanism. Another theory is that crypts melt to adapt to the changing conditions. This second theory is the one which I am more inclined to agree with.
Changes which can cause crypts to melt include changes in; water parameters, light intensity, CO2 levels and temperature. While most plants are likely to show changes in growth when the above parameters are manipulated, only crypts respond in such a drastic way. Recently I converted a ‘dirted tank’ into a high-tech planted tank. The tank contains several species of crypts, which did well with the lower light and CO2 levels. However, when I added pressurised CO2 to the system the crypts began to melt. This not being my first rodeo with crypts, I had expected this to happen. The melting did not start immediately and in my experience it never does. It usually takes 10-14 days from the time something is changed to the time the crypts begin to melt. Over the course of 3 weeks, the crypts melted until every plant was left with one or two leaves. These remaining leaves are a sure sign that the crypts are just melting and NOT DYING!
Here is a photo of the tank before I added the CO2;
Here is a photo of the tank after 3 weeks;
Moving crypts is another trigger for them to melt. Unfortunately, this is why many hobbyists fail with crypts. Crypts that are sold by themselves, rather than in clay or plastic pots, are more likely to melt. This is not necessarily a problem if the crypts are introduced to an established aquarium with stable parameters.
It has been my experience that if you uproot a crypt and move it within the same display tank, it will not melt. Thus, if you have a group of crypts on one side of the aquarium and would like to move a few to another spot, you can do this without too many problems.