I think, starting with the kingdom and working through, it would be 'Animalia' (animals), then 'Chordata' (animals with backbones), then 'vertebrata' and finally 'fish'.
So... well, I think fish are, fish. They're aquatic vertebrates.
Kingdom: Animalia (Animals)
Phylum: Chordata (notochord)
Subphylum: Vertebrata (animals with back bones)
Then, there are three major classes.
The majority of fish belong to the osteichtyes. The study of fish is called ichtyology.
The scientific or taxonomic name would be Gasterosteus spp.
The scientific or taxonomic name would be Tilapia spp.
animal kingdom they are fish
The scientific or taxonomic name would be Cyprinus carpio.
The scientific or taxonomic name would be Ictalurus spp.
The scientific or taxonomic name would be Salvelinus alpinus.
The scientific or taxonomic name would be Gadus morhua.
The scientific or taxonomic name would be Coryphaena hippurus.
The scientific or taxonomic name would be Carassius auratus.
The scientific or taxonomic name would be Melanogrammus aeglefinus.
The scientific or taxonomic name would be Brevoortia tyrannus.
The scientific or taxonomic name would be Esox spp.