At first glance, Relicanth looks like an inferior version of Kabutops or Omastar. However, Relicanth has a few niches, mainly its access to Rock Head. With Rock Head, Relicanth can abuse STAB Head Smash to great effect, punching holes in just about any Pokemon. It also isn't that bad defensively either; 100 / 130 / 65 defenses aren't half-bad for a Rock-type Pokemon.
However, Relicanth is in the NU tier for a reason: base 90 Attack is disappointingly average for a Pokemon with such a potent attack. To make matters worse, it doesn't have a single move in its arsenal with which to boost its Attack. Relicanth is also slow, base 55 Speed means that faster Pokemon can easily attack Relicanth before it can retaliate, though Rock Polish fixes this to an extent. Furthermore, Relicanth has a limited movepool, making it fairly predictable, and a poor typing, which grants it weaknesses to common types in the RU metagame, such as Electric, Fighting, and Grass. However, don't underestimate this bony fish—it has just enough power to rip through unprepared teams.
What better use for a Pokemon that can't boost its Attack than a Choice Band set? Instead of wasting time setting up, Relicanth aims to break skulls with its STAB Head Smash, which is especially good without the recoil thanks to Rock Head. This Relicanth has flawless neutral coverage—it hits every Pokemon in the RU metagame for at least neutral damage. STAB Waterfall has great coverage with Head Smash, as it hits Pokemon that resist Head Smash, such as Steelix, for massive damage. Earthquake nails Magneton, Aggron, and Klinklang, which also resist Head Smash. The last moveslot is a flexible one. Zen Headbutt allows Relicanth to hit Poliwrath, who resists both of Relicanth's STABs, for super effective damage; it also hits all the various Fighting-types in the RU tier besides Gallade and Medicham for super effective damage. On the other hand, Double-Edge hits Quagsire harder, which is just as crucial as Quagsire easily sponges Relicanth's other attacks. Double-Edge also has the benefit of no recoil thanks to Rock Head, so it's a viable alternative over Zen Headbutt.Team Options & Additional Comments >>>
While the Choice Band set focuses on Relicanth's power to break through walls, the Rock Polish set has the aim of sweeping the opponent once Relicanth sets up. This is made easier thanks to Relicanth's great excellent defenses, which mean that defensive Pokemon such as Uxie and Mandibuzz often cannot hurt it much. If it can get a safe switch into a Pokemon it forces out, it can set up and begin sweeping. STAB Head Smash is still the main attack on the set, as it wrecks any Pokemon that doesn't resist it. Head Smash and Waterfall make for a great combo, as few Pokemon resist both attacks. Earthquake lets Relicanth quickly dispatch of Pokemon such as Klinklang and Magneton.Team Options & Additional Comments >>>
This set rose to fame back in the DPP era, and in a tier with Pokemon such as Ludicolo, Qwilfish, and Omastar, it can shine in the BW era as well. By utilizing Relicanth's lesser-used ability, Swift Swim, it aims to use the rain to hit the opponent as powerfully and as speedily as possible. Despite Rock Head no longer being Relicanth's ability of choice, Head Smash still remains the main attack on the set, as its sheer power alone makes it a difficult move to switch into. The combination of Waterfall and Head Smash nails just about every Pokemon in the RU tier—only three Pokemon resist Relicanth's STABs, namely Ferroseed, Poliwrath, and Quagsire. Waterfall is especially dangerous in rain, as it now has the power to take down even more Pokemon. Earthquake is used to pick off Steel-type Pokemon such as Magneton.
Finally, the last moveslot depends on personal preference. Rain Dance enables Relicanth to try and sweep with its own rain, and Relicanth's Waterfall becomes even more powerful. However, if Relicanth's teammates can set up the rain for it, Stone Edge is a viable alternative for a STAB attack that doesn't cause recoil damage, which is crucial when one takes into consideration Life Orb and Head Smash recoil.Team Options & Additional Comments >>>
Relicanth has a few other options it can utilize. A RestTalk set can be viable, but is generally better left to bulkier Pokemon, such as Regirock. Amnesia could work on a defensive set, but Relicanth has better things to do than to try and set up Amnesia. Speaking of a defensive set, a support set with some combination of Stealth Rock, Toxic, and Yawn can work. However, Kabutops and Omastar do it better thanks to higher Attack and Special Attack, respectively, which means that they can deal more damage even with little investment.
Aqua Tail can be used over Waterfall, but it is less accurate, and Waterfall's flinch chance is useful. Substitute shields Relicanth from status, and can possibly give Relicanth an extra attack; however, this takes prediction to pull off correctly. Finally, Bounce forces switches, as well as potentially spreading paralysis, but its charge turn makes it very easy to switch into.
Checks and Counters
Relicanth may have a great combo with Head Smash and Rock Head, but it takes more than that to be a top-tier threat. There are two Pokemon that give Relicanth headaches: Poliwrath and Quagsire. The former resists Head Smash and has Water Absorb to absorb Waterfall, making it an excellent counter. To make matters worse for Relicanth, Poliwrath has STAB Fighting-type attacks to put a dent in it. However, Poliwrath must be careful when switching into the Choice Band set, as a well-timed Zen Headbutt will hurt. Quagsire makes another great Relicanth counter, especially ones with Water Absorb, as it can absorb Waterfall and resists Head Smash. Even Unaware Quagsire does well against Relicanth, though a rain-boosted Waterfall will deal a bit of damage. However, it has Recover to heal off any damage, and thanks to its Ground-type STAB, Quagsire can dispose of Relicanth easily.
Bulky Grass-type Pokemon, such as Tangrowth and Torterra, do a great job of taking Head Smash, though Torterra will not enjoy taking a Choice Band-boosted Waterfall. Ferroseed can also take any attack as it is resistant to both of Relicanth's STABs, though it can't do much in return unless it has Seed Bomb, and without reliable recovery, repeated Head Smashes will hurt. Bulky Fighting-type Pokemon, such as Hariyama, make good checks in general as they can take a Head Smash and retaliate with their STABs, but they must be wary of switching in on Choice Band Zen Headbutt.
Faster Grass-type Pokemon, such as Lilligant and Leafeon, can OHKO Relicanth with their Grass-type STAB attacks before it can attack. However, they must be careful switching in, as Head Smash will hurt. In general, faster special attackers, such as Galvantula and Rotom-C, can beat Relicanth, as they target Relicanth's lower Special Defense. Finally, as Relicanth will most commonly be firing off Choice Band Head Smash, most Pokemon that can take one are safe checks, but note that the right coverage attack will do some damage.