That Crab is the highest paying symbol, paying 5000x the line bet for 5 of them. It's not a Wild symbol, so it cannot and doesn't do anything else. The Boxing Ring is the Scatter symbol, an underwater boxing ring I would presume, 5 of them paying the usual 100x the total bet. In the left corner is the Red Fish and in the right corner is the Blue Fish, both being dumb Wild symbols, because they don't pay for themselves, they don't double any wins and they only do substitution. When each of them appear anywhere on reels 1 and 5, 3 free spins are awarded, with each fish being an Expanded Wild on reels 2 and 4, just like in Playtech's Dolphin Reef game. But why 2 less free spins and not the same? Because Playtech and Microgaming can never the same!
Okay, so what happens when the Red Fish meets the Blue Fish? They fight of course, but not in the way you think they would. Pick which fish you think would win the bout, the red or the blue. Each fish then exchange 2 punches. The third punch knocks the other one out. Either one can be knocked out. If your fish wins, whatever winning combinations on the current reels are doubled. If it loses, all wins remain at par. Simple, yes? Yes. Good, yes? No! At times, the fish you picked would lose all the 3 bouts, and you gain nothing extra from the Free Spins game. Is that any good? Like a dead fish it is! Might as well double all wins from the start, but pay x5 if your fish wins, then that would be more interesting.