Heres some basic info
Grade A Clownfish:More white coloration with much more complex barring patterns than Grade B or C. Barring patterns will connect in atleast one place.
Grade B Clownfish:Have nice patterns but not as much white as a Grade A.The barring pattern is diffirent and not as complex.You can also see Grade B clowns with really nice marking on one side and the other side almost full barring.Almost always Grade A's have complex baring on both side.Grade B can have complex barring on both sides,but it wont be as much white.
Grade C Clownfish:I consider these fish to be nothing but mis-bars with very little Picasso pattern if any pattern of such.
Then you have platinums and snowflakes which will not hava any distinquishable bars and will be mostly white. Snowlakes will have spots of black/orange. Platinums are mostly white.
Grade A
Grade B
Platinum
Snowflake/Snowcasso