Sick fish with red dots

[Creepy the Crayfish]

One of my fish died in the night and when I found him this morning he was dead. He didn't look like he was dying he just was a little less active than the other fish. He had red dots in his eye and on his belly by one of his fins. Does anyone know what this is or how to cure it?

 

[Colin_T]

can you post a picture of it?