Hi Plecomaniac,

Welcome to FishLore.
Does it look like bits of salt? Can you post a picture of it?
Also, your tank isn't big enough for 2 Kissing Gourami. They grow to be 12" each. The rule of thumb is 1" of adult fish to 1 gallon of water.
I see your tank is new, please read about the Nitrogen Cycle:
http://www.fishlore.com/NitrogenCycle.htm
Are you testing your water? If so, with what and what are the readings for ammonia, nitrite and nitrates. The API master kit is recommended over strips. It's much more reliable.
With such a new tank with fish in it, you have to do daily water changes to keep the ammonia levels down.
Sorry for all the questions, but we can better help you by knowing the answers.
Good luck.