I'm new to keeping an aquarium with live plants. I researched low maintenance plants and decided on Anacharis, Anubius Nana, Amazon Sword and Java fern. I put all the plants in the tank with a full spectrum light. Ran the tank for a few weeks while monitoring the water chemistry. Plants all did well, but the Anacharis especially, it took off and was growing like mad. I trimmed it and replanted the trimmings and they took off as well. I put fish in and watched the chemistry cycle. Still all great. Now about a month into having fish in the tank the Anacharis suddenly and quickly is dying. Other plants seem fine. I use RO water but mix it with spring water so the hardness was a little low. But the plants were doing awesome for 6weeks and then boom. I purchased a mineral supplement and applied that, but honestly, the hardness wasn't really that low. Any ideas?