The tank has plenty of nitrates so why do my Java ferns look like this?

I let the roots naturally bury into the gravel so the the roots aren't the problem.
I have not added any kind of fertilizer, but I've always heard that Java ferns don't necessarily need it.
The light I have isn't really dim or anything. I guess it could be a little brighter buts it's not bad.
When I first got these Java ferns there were a couple of hitchhiker grayish snails that just had a bunch of babies. Is that the problem? Or do I just need to add riot tabs or something?
Any advice would be appreciated!

I let the roots naturally bury into the gravel so the the roots aren't the problem.
I have not added any kind of fertilizer, but I've always heard that Java ferns don't necessarily need it.
The light I have isn't really dim or anything. I guess it could be a little brighter buts it's not bad.
When I first got these Java ferns there were a couple of hitchhiker grayish snails that just had a bunch of babies. Is that the problem? Or do I just need to add riot tabs or something?
Any advice would be appreciated!