I'm not sure if it comes and goes, but I'm finding as they get older thus larger, the Green is more pronounced. I've seen the same amount on mine for the last few weeks, so I'm guessing it's permanent.
75g Planted Barbs Denison, BlackRuby, Tiger, Albino Tiger, Green Tiger, Cherry, Gold, Checkered, Odessa.
NonBarbs Cardinal, Neon, RummyNose, Bloodfin Tetras, Z. Danios. 1RTS. Amano, Bamboo, Ghost & RCS. 20g Long Shrimp Tank RCS, Tiger, Amano.