| J.F. Bell Museum of Natural History, Minneapolis |
| J.L.B. Smith Institute of Ichthyology, Grahamstown |
| jack |
| Jacks and pompanos |
| Japan Sea |
| Japanese threadfin bream |
| Japanese trawl |
| Java Sea |
| Jawfishes |
| jaws |
| Jean P. Haydon Museum |
| Jellied eels |
| jellyfish |
| Jellynose fishes |
| jennie |
| Jersey fish |
| Jerusalem Museum |
| jetsam |
| jig |
| jigger |
| jigging |
| jill |
| Jordan's Rule |
| jugal |
| jugular |
| junior homonym |
| junior synonym |
| Jurassic |
| justified emendation |
| Jutjaws |
| juvenile |
| juvenile stage |
