After getting the Zora Mask and rescuing the Zora Eggs, you learn New Wave Bossa Nova and can enter the Great Bay Temple. Just play the New Wave Bossa Nova for Lulu, who is standing behind the Zora Hall in Zora Cape. Then use your hookshot on a palm tree to get onto the turtle's back.
Get a Stray Fairy
In the first room, where the turtle waits, use Deku Sticks or Fire Arrows to light the four unlit torches. If you have no arrows or Deku Sticks, break the barrels to the left of the turtle. The torches go out after a moment, so light them quickly. After all four are lit, a chest appears in front of the turtle. The chest contains a Stray Fairy.
Get a Second Stray Fairy
Go through the door across from the turtle.
In the next room, there is a giant waterwheel. There are also two platforms, one to either side of the door, that go up and down. Wait for the platform to the left to come down, then ride it up. Don't jump down to the rupee platform yet, because there is a Skulltula near the end of it. Kill the Skulltula with an arrow. When it dies, a Stray Fairy comes out. Use the Great Fairy Mask to make it come to you.
Get a Third Stray Fairy
There is another Stray Fairy in this room, floating in a bubble underneath the ledge that you were standing on when you first entered the room. Go underwater as a Zora and swim into that bubble to pop it and get the Stray Fairy.
Turn on the Yellow Spout
As a Zora, and go to the corner of the room where there is a yellow platform underwater with a fish-shaped switch on top. Press B to dive so you are standing on the platform, then grab the fish-shaped switch and push it. This will cause a water spout to turn on. The switch will disappear after this.
Get a Fourth Stray Fairy
Get out of the water and go to where the new water spout appeared, being careful to avoid the Skulltula along the way. Wait for the water to lower, then jump onto it (if you jump into the water when it's higher, it will push you away and you will fall into the water.) Stand on the water spout. When the spout rises, jump to the higher platform. Then follow the ledge to the door where the two water pipes are going. Go through the door.
Hop down to the left and walk along the edge until you reach a ladder. Go up and you find a barrel. Destroy it (you can punch it as a Goron) to find a Stray Fairy.
Get a Fifth Stray Fairy
In this same room, jump into the water and transform into a Zora. While in the water as a Zora, press and hold the A button to continually swim, and use the control stick to move around while holding the A button. Go to the bottom of this room and break the pot in the center to find a Stray Fairy. It can be difficult to hit it because the spinning water constantly pushes you around. Try pressing B to sink to the bottom of this room, then hold the punch button, then release it to throw your fin boomerangs at the pot.
Get the Map
Still in the water, swim up toward the surface. Look for a door just below the water's surface that has a green and a red pipe going into it. There will be fish symbols on the wall pointing toward this door. Go through that door and you will find yourself in a room with some Skullfish. Go to the surface and climb onto a platform, then use the Hookshot on the gold chest to reach it. Open it to get the Map.
Get a Sixth Stray Fairy
The platform across from the chest has two pots on it. Shoot the pots with arrows, or use your hookshot on the pots, or become a Zora and hold the punch button then release it to throw your fin boomerangs at the pots. A Stray Fairy comes out of one of the pots. Wear the Great Fairy Mask to get it.
Get a Seventh Stray Fairy
Now become a Zora again and go into the water. Go down to the bottom of the room by pressing B. Then approach the underwater door that has Dexihands in it. Hold B, then let go to use your fin boomerangs on the Dexihands to kill them. Then hold the A button and move the control stick to swim into the passageway that the Dexihands were guarding. Keep going along this long passageway until you reach the next room.
There are some Bio Deku Babas hanging down in the water. When you hit them, they fall into the water and start running around. Kill them, then press B to go to the surface. Turn around and look for the final Bio Deku Baba, which is hanging from the ceiling. Kill it to make a chest appear. It contains a Stray Fairy.
Get the Compass
Go through the door at the other end of the Bio Deku Baba room.
Hit the two Bio Deku Babas hanging down from the lilypads, then jump across those lilypads. Kill the Real Bombchu (or get close enough so it runs to you, then deflect it with your shield), then use the hookshot on the gold chest to reach it. Open it to get the Compass.
Get a Key
In the same room where you got the Compass, get in the water and put on the Zora mask, then press B to go down to the bottom. Kill the Bio Deku Babas and the Dexihand, then open the chest to get a small key.
Get an Eighth Stray Fairy
In the same room where you got the Compass and key, go to the surface and climb up onto the ledge where you first entered the room. Don't jump into the flowing water, but look at that water to see a jar and some Dexihands. Wear the Great Fairy Mask and use the hookshot to break the jar, then the Stray Fairy will come to you.
Reach the Mini-Boss
Jump into the flowing water, avoiding the Dexihands. Transform into a Zora and hold the A button to swim. You'll be pulled back into the room with the spinning water.
As a Zora, go down to the bottom of the room. There is a red hallway that has fish symbols pointing to it. If you walk toward the wall you will be pushed into this red hallway. Go to the end of the hallway to reach a new room. Kill the Shell Blades and Skullfish if they get in your way, then go to the surface of the water. Walk up the red pipe that is in the water, killing the Real Bombchu in your way. You will reach a ledge that has a locked door. Go through the locked door.
In this room, there are Chuchus and a bunch of jars. The Chuchus will respawn a moment after you kill them, allowing you to get infinite magic and arrows. Break the jars to get additional supplies. Then go through the door at the end.
Look up at the ceiling to start the battle. You can knock the bubbles off of Wart's body with any attack. Try to kill some of the bubbles, then hit Wart's eye with arrows when you have a clear shot. Bomb blasts work well for removing large numbers of bubbles at once and killing them once they are bouncing around. Deku Nuts are even more effective.
After you have hit Wart's eye three times, the bubbles all fall off. The bubbles will continue bouncing around the room for the rest of the battle. Wart will charge toward you, but you can avoid this by standing in a corner and shooting Wart's eye from there. Keep doing this until Wart is dead.
Get the Ice Arrows
After Wart dies, a chest appears. Open it to get the Ice Arrows.
Reach the Second Mini-Boss
Leave Wart's room the way you came in. Go through the green room with the two Chuchus. In the next room, go to one of the southern corners of the room and shoot an Octorok with an Ice Arrow. Then jump on the frozen Octorok and jump up to the switch in the middle. Push it. If it doesn't move, you can pull it, or just push it from the other side.
Get in the water as a Zora and sink down. Go through the blue passageway in the southern wall of the room. You will end up in the spinning water room. Go back through the upper opening that has a red and green pipe going into it. You will be back in the room where you got the map.
Use the hookshot on the gold treasure chest, then shoot ice arrows into the water to create platforms. These platforms melt after a while, but you can walk on them until then. If you become a Deku Scrub, you can hop over the water to reach the ice platforms that you create. That way, you do not have to create very many ice platforms to reach your destination. Create ice platforms so you can reach the door at the end of the room. Go through.
Freeze the Chuchu in this room with an Ice Arrow. Push the frozen block to the red platform. Then press B to climb on the frozen Chuchu. Jump from it onto the platform with the switch on it. Raise your shield to deflect the Real Bombchu up there. Push or pull the switch to turn it.
Leave this room the same way that you came in.
Back in the room where you made frozen platforms using ice arrows, become a Zora and sink to the bottom. Kill the Dexihands in the passageway, then swim through that passageway. At the end, you will be in a narrow room with lilypads. Go to the surface of the water, then go through the door in this room.
Shoot ice arrows into the water to make platforms so you can reach the passageway that has icicles in it. You can hop from ice platform to ice platform as a Deku Scrub. When you reach the other side, break the icicles to get magic and arrows, then use a fire arrow to melt the door. Go through.
Run after Gekko while avoiding the blobs of Mad Jelly. You can deflect the Mad Jelly with your shield or hit them out of the way with your sword. Run after Gekko and hit it with your sword when you get close. Then he will go up to the ceiling in a giant blob of Mad Jelly, moving the jelly with him. He will try to make the jelly fall onto you. If he does, you will be trapped in the jelly and he will attack you until you pop out. Run away from the shadow of the jelly, then shoot the Mad Jelly with an Ice Arrow while it is still on the ceiling. It will freeze and fall to the floor and shatter, leaving Gekko vulnerable. Be sure to get out of the way of the falling ice or you will get hurt. Run after Gekko while avoiding the Mad Jelly and hit Gekko with your sword when you reach him. The jelly will come back together and go to the ceiling. Repeat the process until you have defeated Gekko. He turns into a normal frog.
Get the Boss Key
Exit Gekko's room through the door on the left. Then follow the path and open the chest to get the Boss Key.
Climb up out of the hole in the gold fence to leave the enclosed area. Or you can use the hookshot through that hole to get out. Jump into the flowing water in the southeast part of the room, but avoid the Dexihands that are in there. The flowing water will send you back to the spinning water room. Go up to the surface of the water and climb onto a ledge. Go to the door of the room that has a yellow and red pipe in it. Go through.
Change the Water Flow
You will be back in the first room. Look at the ceiling to the right of where you entered. There is a hookshot target there. Use your hookshot on it and you will land on the water spout. This water spout turned on because you activated the red switch in the room where you froze the Chuchu. Use this water spout to reach the red switch in this room. Turn it. The water wheel stops spinning. Now go over to the yellow switch near the middle of the room and turn it. This makes the water wheel spin again, but in the other direction. Go to the door and ride the platform up to the ledge near the yellow spout of water. Jump on the yellow spout of water, then jump to the ledge across the way. Go through the door at the end of this ledge to reach the spinning water room again.
Get a Ninth Stray Fairy
Jump onto the spinning platform. Use the platform to reach the other side, where a waterfall is blocking the ladder. Use an Ice Arrow on the waterfall, then climb up the ladder. Go through the door at the top.
Use the hookshot on a barrel to reach that platform. Then look up at the northwest corner of the room to see a hole in the ceiling. Use Ice Arrows to create frozen platforms in the water that you can hop to as a Deku Scrub. When you are under the hole in the ceiling, use the hookshot to reach the upper area. Go to the middle and open the chest to get a Stray Fairy.
Get a Tenth Stray Fairy
Go back down below the ceiling and use Ice Arrows to create ice platforms, then hop to them as a Deku Scrub to reach the platform with the switch on it. Turn the switch. Then exit this room the way that you came in.
In the room with the spinning water, get in the water. It's rotating the other direction now, so you are able to enter a different set of doorways underwater. As a Zora, go through the upper passage that the water pushes you into. It's green and has a red and green pipe going into it. Go through this passageway, but be careful of the Dexihands along the way. This is the room where you got the Boss Key. Continue going through the flowing water to reach the next room.
The next room has spiked mines, so quickly go to the surface to avoid them. Go to the corner of the room where there are some barrels, then get on the moving platform that comes down next to it. When the platform goes up, jump onto the rotating crankshaft, then walk on that crankshaft to stay on top. Then when the next platform comes over, jump onto it. Before you get off of this moving platform, use the hookshot on the torch in the little room to reach a chest. Open it to get a Stray Fairy.
Get an Eleventh Stray Fairy
Make your way back up to the platform that is moving side-to-side. When the platform moves to the opposite side, jump off and walk along the ledge to the end. Freeze the water that is pouring down from the ceiling, then jump onto the platform that just stopped rotating. Walk along the crankshaft and get up on the water wheel. Walk up one of the spokes of the wheel, then use the hookshot on the chest in the little room in the north wall. Open it to get a Stray Fairy.
Get a Twelfth Stray Fairy
Jump back down to the crankshaft and walk across it to the end. Walk to the upper exit and go through.
Jump down to the watery floor and stand on the see-saw in the bottom-right corner of the room. Look at the ceiling and melt the ice block with a fire arrow. When the see-saw goes up, go under the end of the see-saw that went up. As a Zora, sink to the bottom and you find a small hidden room. Break the barrel to get a Stray Fairy.
Get a Thirteenth Stray Fairy
Go back up to the see-saw level. Get on the next see-saw and melt the ice above it to go farther up. Jump to the green switch and turn it.
After turning the green switch, transform into a Zora and walk along the green pipe with the Real Bombchu on it. Kill the Real Bombchu before you go past. Then go to the far end and climb up the pipe (you have to be a Zora to be tall enough to climb it). Walk along the pipe to reach the enclosed area. Use your hookshot to reach the chest. Open the chest to get a Stray Fairy.
Get a Fourteenth Stray Fairy
Go back to the floor and stand on the one see-saw that still has ice above it. Melt that ice with a fire arrow, then go through the passageway that you can now reach.
This is the room where you got the map. Get in the water as a Zora and sink down so you can go through the submerged passage back to the central room with the spinning water. Sink to the bottom and go through the yellow passageway at the bottom that the water pushes you into.
In the same room, look in the passageway that you didn't enter through. There is a Stray Fairy in a bubble there. Don't go into the passage. Instead, use your fin boomerangs (hold the punch button then let go) to break the bubble, then wear the Great Fairy Mask to make the fairy float to you.
Get a Fifteenth Stray Fairy
There is a Stray Fairy underneath the central platform, between the wooden pillars. Try going to the surface and standing on the green pipe, then use an arrow or the hookshot or the fin boomerangs from there to pop the bubble. Wear the Great Fairy Mask to make the fairy come to you.
Reach the Boss
Rise to the surface and walk on the green pipe to reach the green switch. Turn it to create a water spout. Wait for the water spout to go down, then jump on it, then wait for it to rise, and jump from there to the boss door. Open it. You'll be in an empty room with a big hole in the middle. There are no jars or anything up here, so just fall into the hole.
To do well in this battle, you have to understand how to change direction when you swim as Zora Link. You can press the A button underwater to swim as a Zora, but if you hold the A button, you will swim continuously. Use the control stick while swimming and you will change direction. If you swim at a sharp angle toward the surface of the water, you will jump out of the water, much like a dolphin. This is useful for quickly getting out of the water and onto a ledge, but it can be tricky. If you don't use these techniques, the Gyorg battle will be difficult.
During the battle, Gyorg will swim around the platform for a while, then it will eventually ram into the platform, making it shake. You will be knocked over when this happens, unless you jump backward or sideways at just the right moment. If you don't jump, and you are too close to the edge when the platform shakes, you might get knocked into the water.
Being in the water is very dangerous, because Gyorg can swallow and chew you, damaging you by two hearts. If you have to be in the water at any time during this battle, transform into Zora Link so you can quickly swim to the middle ledge and try to dolphin jump out of the water as described a couple of paragraphs ago.
To damage Gyorg, first you have to stun it while it is swimming around. You can do this either by shooting an arrow at it (the quickest method), or by using your hookshot, or by using Zora Link's fin boomerangs (hold the punch button then release it to throw the boomerangs).
After stunning Gyorg, inflict damage with Zora Link's electric barrier attack. To do that, jump into the water as a Zora and hold the A button to swim continuously. Use your control stick to swim toward Gyorg (you might want to swim slightly away at first so you can turn and aim more accurately at Gyorg), then hold the R button to use your electric barrier attack to damage Gyorg. Then quickly swim away and get back onto the middle platform.
If you run out of magic, there are magic jars underwater in the corners of the room.
After you have stunned and damaged Gyorg three times, he spits out mini-gyorgs. You can easily defeat these if you use the electric barrier (hold R while in the water as Zora Link). Repeat the strategy to damage Gyorg four more times. Then it will die.
Take the Heart Container and then step into the glowing spot to get Gyorg's Remains. Watch the cut scene that follows.
Afterward, you can rehearse with the Indigo-gos, although you don't get any rewards for doing so. To rehearse with them, go into the cave next to the Zora Cape owl statue, then go to the rehearsal area where the other Indigo-gos are, and talk to Lulu as a Zora. You will rehearse with the band.
Increase your Defense
If you have all 15 Stray Fairies from Great Bay Temple, then go out to Zora Cape, go to the square stone platforms on the beach, then jump from platform to platform until you are on a ledge with a boulder. Go toward the edge where you can see an island with a palm tree. Use the hookshot on the tree to go there. Do the same thing to go to the next two islands. From there, jump onto the tall stone pillar, then jump to the ledge beyond that. Use a regular bomb or the Blast Mask on the boulders here. Go into the cave. This is the Great Fairy Fountain. If you collected all fifteen Stray Fairies in the Great Bay Temple, this Great Fairy will increase your defense.
Go Toward the Valley
Go east from Clock Town to reach Ikana Valley.