Cryptocoryne blassii

By Ronald B. Finlayson
From the November 1999 issue of "The Daphnian", Boston Aquarium Society
Aquarticles

Crytocoryne blassii is one of my favorite aquarium plants. It will grow to more than 24" in height with leaves that are 6" long, 3" wide and are a deep olive green on the top and a wine red color underneath. Truly an impressive plant.

I have grown this plant for several years and until recently have had little success getting it to reproduce by runners. This was in a planted tank with a laterite substrate and CO2 to boot. The plant always looked great and got very large but it never produced the runners that I had hoped for.

Finally in frustration I removed one plant from my 90 gallon, which had been planted in the same location for approximately 3-4 years. This was a very large C. blassii - easily 24 plus inches in height and in great shape. The only problem was it had never reproduced!

I took this plant and potted it up in a container with a prepared mix which included:
1. Garden soil from behind my house
2. Peat moss
3. Chelated iron
4. One half of a pond tab (which is a fertilizer used for water lilies)

After planting the blassii in the pot I spread approximately ½ inch of #0 or #1 natural gravel on the top of the pot. This keeps the soil from clouding the tank and at the same time does not restrict any plant growth. It is also important to keep the crown of this plant above the gravel.

I also moved the plant to the back of the tank and positioned it just downstream from the filter discharge, which also doubles as a reactor for my CO2. This means the plant has a constant flow of CO2 across its leaves.

C. blassii is different than any other Cryptocoryne in that it likes to be planted and remain undisturbed for long periods of time. Constant moving of this plant will prove detrimental to its well being and will result in a frustrating experience for the aquarist. To this end make your decision as to where and how you want to plant this Crypt and stand by it. Also, remember that most likely this Crytocoryne comes from an environment that is both boggy and rich in nutrient material.

After a few months my plant started to take off and within six months this one plant, that had done nothing in three years, had produced four plants in a container 4" across and 4" high and was attempting to climb out of its pot!

On December 5, 1999 I unpotted this plant and repotted five individual specimens. My conclusions from all this:
1. C. blassii likes a very rich humus substrate.
2. CO2 will encourage growth but may not be necessary.
3. Artificial fertilization and chelated iron is definitely a plus.

To this end I will, from this point forward, always plant this Crypt in a nutrient-rich substrate. If you are experiencing this same problem you may want to try this method as well.