Tabuai-Fidow, playing centre, started the match four tries behind Sydney Roosters whiz Mark Nawaqanitawase (23) on the NRL season leading try-scoring list.
The man known as "Hammer" got to 22 before leaving the field in the second half with a medial collateral ligament (MCL) injury which may have implications for the post-season international Tests, whether he chooses to play for Australia or Samoa.
AAP has been told he is leaning more toward Samoa.
The Dolphins claimed ninth position on the ladder with the final-round victory at Redcliffe, their highest-placed finish in three seasons in the NRL.
Their 12 wins were the most they had achieved in a season and they finished the year with 721 points scored, the best of any team in the NRL. The 62 points scored on Sunday was also their best ever.
"To finish ninth and score more points than any team in the competition, it's outstanding for us and outstanding for our attack, but we know we need to be better defensively," Dolphins coach Kristian Woolf said.
"It's what we've had to build on for the last three years to be fair, and when we find that we'll start to see what we're capable of."
Nicholls, known as GOAT, scored with his first touch off the bench and the popular prop converted his own try in a moment to savour in his 194th and final game.
The Raiders rested 11 of their top squad and gave NRL debuts to outside backs Manaia Waitere, Kane Anderson and Michael Asomua along with back-rower Joe Roddy.
"We were on the back foot for 70-odd minutes. Those types of scenarios they faced was a great learning curve with regards to what happens in the NRL if you are not up to a standard," coach Ricky Stuart said.
Asomua, a brute of a winger, scored on debut while Roddy notched a second-half double.
Warhorse Corey Horsburgh captained Canberra for the first time while, in good news ahead of the finals, back-rower Matt Nicholson returned from a syndesmosis injury for his first NRL match since round 10.
The minor premiers have their sights on Brisbane in Canberra in next Sunday's qualifying final with the result of the match against the Dolphins immaterial to them.
The Dolphins will look back on this year as an opportunity lost after getting as high as sixth after round 15 before three consecutive losses, to Sydney Roosters, Brisbane and Manly, scuppered their chances.
The rise and continued development of fullback Trai Fuller, winger Tevita Naufahu, utility Kurt Donoghoe and back-rowers Kulikefu Finefeuiaki and Oryn Keeley have been highlights after a well-documented injury-ravaged season.
The addition next year of Brisbane outside back Selwyn Cobbo and St Helens forward Morgan Knowles will add class. They just need to get more defensive clout.
Naufahu, who scored a double, had a blinder on Sunday. Fuller, half Isaiya Katoa and Tabuai-Fidow showcased their class as the home side took a 30-0 lead at the break.
Dolphins centre Jake Averillo also scored a double.
Raiders forward Morgan Smithies was put on report for a dangerous tackle on prop Josh Kerr.
Dolphins winger Jamayne Isaako finished the season as the NRL's leading points-scorer for the second time in three years.
