Velvet disease, also known as Gold Dust Disease, is caused by a dinoflagellate parasite of the genus Piscinoodinium. The disease is most common in fish that live in tropical and marine aquaria. The life cycle of the parasite has three major phases: the organism divides, then uses photosynthesis for growth, then the parasite infects a fish host. Symptoms include flash swimming, lethargy, visible topical “dusting” of colonies on the fish, and necrosis of gill tissue. Treatments include sodium chloride, copper sulfate, methylene blue, formalin, malachite green, and acrifiavin. This parasite is not transmissable to humans.