Fishworm and Red worm

Fishworm noun - Terrestrial worm that burrows into and helps aerate soil; often surfaces when the ground is cool or wet; used as bait by anglers.

Red worm is a synonym for fishworm. In some cases you can use "Red worm" instead a noun "Fishworm".

Red worm noun - Terrestrial worm that burrows into and helps aerate soil; often surfaces when the ground is cool or wet; used as bait by anglers.

Fishworm is a synonym for red worm. You can use "Fishworm" instead a noun phrase "Red worm".