Freezing fresh water fish
I grew up fishing and preserving the fish. We would only freeze and brine if we intended to smoke it later, we would would then re-brine it after it thawed (great way to make Northern Pike Jerky btw).

For smaller species like crappie, yellow perch and bream I wouldn't bother, as they freeze fast enough and consistent enough on their own. Key things to look out for would be ensure it's sealed tight, frozen flat (for easy storage and thawing), and descaled (if it's your preference) for some reason I am not sure why but descaling a previously frozen fish isn't terribly effective.

Good luck and tight lines.