Here's my experience: Melafix and Pimafix are worthless for treating established infections. The bloody streaks sound like secondary bacterial infections from infestation by Ich or other parasties. Treat with antibiotics. Treat now. Use Maracyn and Maracyn 2. Or API's EM Erythromycin and TC Tetracycline. I did a Melafix/Pimafix course and that wasted time probably cost my last moor its life.
If I could do it over again, I would have dosed the tank with antibiotics the day I started treating for Ich.