I have a tank that was primarily Anubias nana petite. Was being the key word. For some reason the rhizomes seem to be rotting away. The tank is pretty hi tech, 4wpg, pfertz and pressurized co2. For the first 5 months things were growing great, but then this year the rhizomes keep rotting away/dying. The leaves on the rhizome will be alive, but the stem/rhizome area would melt. I really don't know what to do, there is still new growth etc, and just a little bit of GSA on some of the leaves. The plants are tied onto driftwood and not buried or anything like that. Could this be some sort of disease/fungus/mold?