Billy did a wonderful job creating his whimsical[,] clay fish dish.
I respectfully disagree with Konrad’s answer.
When two adjectives precede a noun, the first adjective may modify the combined idea of the second adjective plus the noun. In such cases do not separate the adjectives by a comma.
—The estate is surrounded by an old stone wall. (A ‘stone’ wall that is ‘old’.)
—Here is the annual financial statement. (A ‘financial’ statement that is ‘annual’.)
TEST: To decide whether consecutive adjectives should be separated by a comma or not, try using them in a relative clause after the noun, with ‘and’ inserted between them. If they read smoothly and sensibly in that position, they should be separated by a comma in their actual position.
—We need an intelligent, enterprising person for the job. (One can speak of ‘a person who is intelligent and enterprising, so a comma is correct.)
—Throw out your old down coat. (One cannot speak of ‘a coat that is old and down, so no comma should be used in the sentence.)
Whimsical clay fish dish is like old stone wall; the stone wall is old, and the clay fish dish is whimsical.
Here are several tests to recognize equal adjectives:
- Insert and between them. If the sentence still flows smoothly and makes sense, the comma is correct.
Thank you for your helpful and detailed report. (Flows smoothly and makes sense. Needs the comma when and is omitted.)
Thank you for your helpful and monthly report. (Does not make sense because it sounds like two reports. The adjectives are not equal and do not need a comma when and is omitted.
You would not say whimsical and clay fish dish, so no comma is needed.
The websites http://englishplus.com/grammar/00000072.htm and http://www.quickanddirtytips.com/education/grammar/commas-with-adjectives add an additional proof:
If you can reverse the order of the adjectives, use the comma. Consider the above example, We need an intelligent, enterprising person for the job. You could just as easily say We need an enterprising, intelligent person for the job. Use the comma (or and).
But you can’t say clay whimsical fish dish, so no comma.