| 1a. | Dorsal fin followed by two or more finlets | Family Scombridae Mackerels and Tunas |
| 1b. | Dorsal fin followed by one finlet or none | 2 |
| 2a. | Dorsal entirely of soft-rays | Family Bathymasteridae Ronquils |
| 2b. | Dorsal fin with spines and soft-rays | 3 |
| 3a. | Dorsal fin with only 3 or 4 spines | Family Bramidae Pomfrets |
| 3b. | Dorsal fin with 5 or more spines | 4 |
| 4a. | Anal spines present | 6 |
| 4b. | Anal spines absent | 5 |
| 5a. | Lips fringed; suborbital stay absent | Family Trichodontidae Sandfishes |
| 5b. | Lips not fringed; suborbital stay present | Family Cottidae Sculpins |
| 6a. | One or two anal spines | Family Sciaenidae Drums |
| 6b. | Three anal spines | 7 |
| 7a. | Preopercle without spines (may be weakly serrated) | 9 |
| 7b. | Preopercle with spines | 8 |
| 8a. | First 3 or 4 dorsal fin spines greatly elongated | Family Zaniolepididae Combfishes |
| 8b. | Anterior dorsal fin spines not greatly elongated | Family Scorpaenidae Scorpionfishes |
| 9a. | Two dorsal fins | 11 |
| 9b. | One dorsal fin (may be deeply notched) | 10 |
| 10a. | Six to eleven dorsal fin spines; suborbital stay absent | Family Embiotocidae Surfperches |
| 10b. | Dorsal fin has 16-28 spines; suborbital stay present | Family Hexagrammidae Greenlings |
| 11a. | Opercle has two spines | Family Moronidae Temperate Basses |
| 11b. | No opercular spines | 12 |
| 12a. | Two lateral line canals, main line composed of heavy scutes and extending length of body, accessory line extending along base of dorsal fin | Family Carangidae Jacks |
| 12b. | Single lateral line canal | Family Anoplopomatidae Sablefishes |