Ich?

[Humblefish]

The speed with which the life cycle is moving is very telling. I the pictures it seems pretty clear that velvet is a real concern. The spots are numerous and most of them are very small - consistent with velvet. Either way, copper will treat both so all bases are covered.

^^ This. When in doubt, copper (or CP) it out.

 

[jenreefer]

If I understand the lifecycles properly, ich will develop slower than velvet. If it shows up very quickly in large number is it more likely velvet than ich. Ich penetrates deeper and has to grow into something that can be seen. This takes more time. Velvet stays closer to the surface so becomes visible more quickly.
Even knowing this, I still can't tell the difference by looking at most pictures. I try to stay very active on this section of the forum but there is nothing like the hands on experience in seeing hundreds or thousands of cases that Humblefish and Melypr have seen.

Another basic but not 100% rule is if you can count the dots prolly ich, if all over the body and too many to even think about counting, then prolly velvet. This does not preclude the possibility of both occurring on the same fish. My experience with ich is that the first sign of it is a solitary or pair of grains of salt on a fin. This will stay like this for 4 days or more before disappearing. With Velvet, in my experience, the first sign is very small grains all over the body. Just my two cents. Humblefish and Melypr are indeed quite knowledgeable on all things fish disease.

 

[Humblefish]

Another basic but not 100% rule is if you can count the dots prolly ich, if all over the body and too many to even think about counting, then prolly velvet. This does not preclude the possibility of both occurring on the same fish. My experience with ich is that the first sign of it is a solitary or pair of grains of salt on a fin. This will stay like this for 4 days or more before disappearing. With Velvet, in my experience, the first sign is very small grains all over the body.

Excellent observations!