Based on this information, what is Fishie's phenotype for the body color trait?

 - a gray body
 - a golden body
Fishie's genotype for the body color gene is bb. Fishie's genotype of bb has only b alleles. The b allele is for a golden body. So, Fishie's phenotype for the body color trait must be a golden body.
To check this answer, consider whether Fishie's alleles are dominant or recessive. The allele for a golden body (b) is recessive to the allele for a gray body (B). This means B is a dominant allele, and b is a recessive allele.
Fishie's genotype of bb has only recessive alleles. An organism with only recessive alleles for a gene will have the recessive allele's version of the trait. So, Fishie's phenotype for the body color trait must be a golden body.