you can find it in the routes of 126 to 127 you have to dive in the water though
No, Relicanth does not evolve.
Relicanth appears in Pokemon Ruby, Sapphire, Emerald, Diamond, Pearl, Platinum, Heartgold, and Soulsilver. In Ruby/Sapphire/Emerald you can catch it pretty much anywhere in the Underwater, using Dive in the sea. In Diamond/Pearl/Platinum, you can catch it by using a Super Rod on Route 226. And in HeartGold/SoulSilver, you catch it on Route 12.
Relicanth doesn't evolve
you find relicanth by mosdeep city.
No, Relicanth does not evolve.
Yes, it always has to be Wailord and Relicanth - Relicanth in the first slot and Wailord in the last in Ruby and Sapphire, and Wailord in the first slot and Relicanth in the last in Emerald.
You can find Relicanth underwater, but they are rare.
nothing evolves into relicanth and relicanth does not evolve
relicanth for sure.
I got mine fishing with a super rod on route 226. I got it on my first try but it is probably really hard to find.
I caught a Relicanth last night completely by surprise. I was surfing at the top of the water on Route 226 (above the guys who teaches you the elemental hyper beams) and i faced a rock (leaving enough water in front of me to fish) and started fishing with a Super Rod. I was looking for a Seadra but came across Relicanth so i caught it. (Still looking for the Seadra haha) Hope that helps!
you will find relicanth underground under sotopolis city (note relicanth is super rare it will take for ever to find