Here's why:
* Ray-finned fish have fins supported by thin, bony rays. These are the most diverse group of fish, comprising about 99% of all fish species.
* Lobe-finned fish have fleshy, lobed fins supported by a bony axis. This group is much smaller, with only eight living species, including lungfish and coelacanths.
Perch have the characteristic thin, bony rays supporting their fins, which classifies them as ray-finned fish.