Hmmm could be one of two types I think - either a Smokey or a Half Black. Did you get them as a specific strain? If its just a general Angel it wont be a strain as such but just uniquely marked.
Didn’t get a strain, they were brought from my lfs from an assorted tank of a variety of different types. Some are all black, some silver with black stripes, this one is the odd one out with the kind of spoldge. Be interesting to see as it gets older
In my part of the world, it's a marbled. If you breed them you get all kinds of degrees of pigment. The marketing names are pretty meaningless, and often regional.
It is Pterophyllum scalare. After that, you can call it a half grey smokey running out of printer ink blue cheese chocolate marbled.