HELPPP! Tinny bug that run in a zig zag pattern in my dogs hair!?

So I have 3 shih tzus, 2 girls and 1 boy. the girls had like 1000 very little bugs on them when we gave them a bath they look like fleas but they didnt jump at all! they stuck to them we hard to brush them really hard to get them off. Are they fleas? the boy has like 4 on him, and they are all around eachother so the girls have a sweeter smelling conditioner than the boy could that be why he barely has any? the bugs ran in a zig zag pattern you couldnt see the bugs on them when they where dry but the secound they got when the bugs ran in a rig zag pattern? are they fleas? PLEASE HELP ME!