Java Fern Discoloration

[icydeath]

Okay so my Java is doing well and I have a bunch of daughter plants and more are growing on it rn but I noticed one of the leaves is getting a red stem and white leaves near the rhizome. The others aren't getting this.

What is causing this?

Thanks in advance.

 

[Mattyfelts]

is the rhizome buried? we need details.. parameters, lighting, tank size, stocking... blah

 

[icydeath]

It is in a 5 gallon tank with two otos, a betta, and a nerite snail. It isn't planted. My parameters are 0, 0, 0. I know it is getting enough nitrogen though because I have a bunch of planted daughter plants from it and my betta drops atleast one pellet a day so I am already getting ammonia from that. I've had it for around 5 months. It is lit with a 20" floramax bulb (fixture is made for a 10 gallon). I'm dosing liquid CO2 and florapride. I do a 15-20 percent water change weekly.