Green? Never even saw fish lice in that color. Use dimilin powder though I suggested the use of Sera Cyprinopur when my lfs had a case of fish lice before.
Dimilin Powder
The only known method of killing this parasite, without killing the fish is DIMILIN POWDER which can be used safely at any water temperature and has an action of sterilizing the adult and larval stages of this parasite which insures that all eggs produced, after the application of Dimilin, will not hatch.
Method: Dimilin Powder at the rate of 1 gram per ton of pond water. Measure out the quantity required and mix in a plastic bucket with pond water ensuring that the powder is dissolved then add to the pond in the previous manner. A second dosage may be needed to ensure that the life cycle of the anchor worm has been halted. After this second application the dead adults, which will still be hanging from the fish, can be removed using tweezers but making sure that the hooks, as well as the tail of the anchor worm are removed and then apply a proprietary topical dressing to prevent a secondary infection.