Cryptocoryne Cordata Var. Siamensis ‘Rosanervig’ Submersed

Cryptocoryne Cordata Var. Siamensis ‘Rosanervig’ is a very rare yet controversial plant due to it’s white/pink veining that no one has been able to put a thumb on. We do know that the veining is due to a virus, however the veining seems to either be very pronounced or not pronounced at all depending upon the set up they are in.

I have seen this species under high light conditions (60+ PAR) with it’s veining still present and very deep, while also seeing this species in another set up with med/high light where hardly any veining is pronounced.

For me personally I have only been able to get deep/rich white/pink veining to display under lower light conditions like you’ll see with this runner hidden behind a piece of driftwood…

IMG_1804 IMG_1805

HOWEVER; I also have a runner in the front of my tank where the light is MUCH brighter (60+ PAR) and you can clearly see a pronounced pink/white vein, although it is not as “thick” as the one hidden behind the driftwood.
IMG_1795 IMG_1794

This is a new leaf forming off the mother plant, the mother unfortunately does not have the greatest veining but the plant is an absolute monster at almost 18+ inches tall and constantly sending 10-15 runners every 6-8 months.
IMG_1798 IMG_1799 IMG_1800

Here are more runners, in total I have six runners currently popping up, all ranging in size from tiny plants just forming to daughters that have 2-3 leaves.

IMG_1796 IMG_1797

As always here are the specs the plant is kept in:

PH- 7.4 at night, 6.5 during the day when CO2 is on.
Temperature- 74-76
Lighting- 30″ Dual bulb T5HO – 6700k and Rosette bulb (10 hours per day). 24″ Dual bulb T5HO – 6700k and Rosette bulb (8 hours per day)
Filtration- Marineland C220 Canister Filter
Substrate- Flourite Dark, Flourite Red, Flourite Black Sand, Muriate of Potash, Dolomite, Mineralized Top Soil, and Natural red clay from the earth.
Water Changes- X 1 a week 50%
Dosing- Alternate Micro and Macro ( 1 day Micro, 1 Day Macro, etc) KNO3, KH2PO4, KS2O4, and Plantex CSM+B.
CO2 – Dual Stage Concoa 212 with Parker H3l, Fabco Solenoid, bubble counter and 15LB CO2 Tank. 2 BPS via inline diffuser on canister outlet line.

Cryptocoryne Cordata Var. Siamensis ‘Rosanervig’ Emersed

In the past 6 months I’ve had my Cryptocoryne Cordata ‘Rosanervig’ send 8 runners which has allowed me to experiment with it’s growing conditions. Up to date I’ve kept this plant submersed in medium light with CO2, E.I dosing and a very nutrient rich substrate but because of the excess amount of plants I have I decided to try some emersed in low light.

Most of the plants are still adapting to emersed conditions but it’s interesting to see the different leaf formations/patterns all within one plant; it’s easy to see now how this plant can be mistaken for another if grown improperly. I personally do not have a large enough tank at the moment to keep this plant under it’s proper conditions which is why I have it under medium light & it isn’t displaying it’s veins.

From my previous research and experimentation with this plant I’ve found that keeping it light conditions under 20-30 PAR really bring out the veins, to increase the pink coloration I’ve found it to be a matter of increasing phosphates, contradictory to other experts advice.

Enjoy the pictures, and as you will see in them the Cryptocoryne Cordata ‘Rosanervig’ is truly a beautiful plant when it’s veins are displayed.

IMG_1365 IMG_1370 IMG_1369 IMG_1371  IMG_1366

As you can see I have many to experiment with in emersed conditions 🙂

Kirk Gibson

Cryptocoryne Cordata Var. Siamensis ‘Rosanervig’


I was lucky enough to get this plant a little over a year ago from a well known hobbyist here in Canada. When I first got the plant it only had two small leaves on it and took roughly 4-5 months to adapt and start forming a new leaf. I unfortunately had to move a short while later so it never had a chance to fully get established, nor did it enjoy the water parameters it was in (very hard water PH 8.2+). After I moved the water parameters which much more favourable (PH 7.5) but with the addition of pressurized CO2 I’ve been able to bring the PH to a stable 6.5. This is where I’ve found the Cordata ‘Rosanervig’ is happiest and has sent 4 runners for me in the last 6 months and roughly 1 new leaf every two weeks/three weeks. It was not easy to figure out exactly what the Cordata Rosanervig preferred but with much patience and experimentation I believe I’ve found it’s ideal conditions.

I’ve done many experiments with substrates, lighting, water parameters, and fertilizing and this is what I’ve found.

1st attempt  (FAILURE)
– PH 8.2 (Water was too hard)
– MGOCPS with silica sand cap (Anaerobic conditions formed and the plant was not happy)
– Tank was near a window (Plant does not enjoy high lighting)
– Excess lighting+nutrients caused algae to form and veins to disappear.

2nd attempt
-PH 6.5 (Nice and soft)
– MTS+Dolomite+Muriate of Potash+Natural Clay + Seachem Flourite Dark X 1, Red X 1, Black Sand X 2.
– E.I dosing, micro + macro nutrients
– Pressurized CO2 10PSI 4 BPS