Is the ick treatment safe for my fish?

I have 1 male betta, 6 neon tetra's, and I just bought (with the ick treatment) 3 golden tetra's. 10 gallon tank. The ick treatment is called "wardley essential's ick away". My tetra must have ick, I see little white spots all over his body. And his behavior is different than the others. It says on the label that tetra's can be sensitive to ick treatment. Will this be safe for them? I still have the gold tetra's floating in the tank, should I let them out of the bag and treat them too? And I've just treated the water with water conditioner, do I have to wait to treat it with ick treatment now?