I bought a six line when I first noticed the problem, because they are tiny,most of them about the size of a comma in 12pt font. But it's not interested, and the tank is too small for a leopard wrasse....I even considered damsels, but they are so evil, and all of my other fish are so peaceful. So it looks like I will do the siphon, double dose, water change and repeat in 2 weeks that was suggested, and hope that works.