Velvet 

Velvet is a parasitic protozoan, much like ich. There are different species of velvet in fresh and marine, however symptoms are usually the same. The main difference is that velvet will be more gold/coppery in color. Velvet is a much faster moving disease than ich, and typically a quick killer. The life cycle of velvet averages 4 days, rather than 7 days in ich. The major life events for these dinoflagellates are very similar to ich, with one big exception; the free-swimming stage of velvet is photosynthetic. This means that although it has a shorter life span than ich, velvet can remain infectious for roughly the same amount of time. Once velvet is noticed, time is of the essence. 

The first symptoms to be noticed are going to be flashing, White Spots, swimming in the flow of a powerhead or trying to stay out of the light, as velvet causes light sensitivity. The ich looking white spots will suddenly explode all over the body in a matter of hours to days. As one R2R user suggests, "If you can count the number of white dots on your fish, then you are probably dealing with ich. If they are too numerous to count, it is most likely velvet."