white "chalk-like" coating on Java Fern

[ringfinger]

I am asking this question for my brother whose tank I have not seen for a few months. He doesn't have a test kit, but his tank is a very simple low light 10 gallon with a Dwarf Gourami, Ghost Shrimp, Otocinclus, and a couple Apple Snails. Lately he has been describing this white "chalk-like" coating on the leaves of his plants. He says that it quickley spread to many of the leaves until he removed all those that were affected this weekend. No sign of it starting up again, but it has only been 2 days. He also said that it was enough to completely block out any visible coloration on the plants. I kinda thought it was a fungus, but without a picture I'm not sure... Anyone had a similar experience or know what this might be? Would Melafix work, or is that a bad idea with the Gourami?

 

[CGGorman]

I got the same thing on a Java Fern in my Betta tank after using a medication that contained Melaleuca. The relationship could be coincidental, though. It is the only plant in the 1/2 gal Betta tank. The Betta is the lone finned wonder in said tank.

I took the Fern out and rubbed all the leaves with my fingers under running tap water. The chalk came right off, so I replanted the thing. Almost two weeks later, now, and it has not returned.

Water parameters have not changed. Only difference I can come up with is that medication.

Two weeks after the scrubbing:

 

[ringfinger]

I know my brother hasn't used any medication. Weird. Good looking tank by the way...

Nobody else seen this type of thing?

 

[malkore]

I've grown pounds of normal, narrow and windlove java ferns...never seen any white, chaulk like stuff on any of them.