Clash of Clans Hero Pet Upgrade Priority Guide

To get the highest return on your Dark Elixir, prioritize upgrading the Spirit Fox, Unicorn, and Phoenix first. These three companions provide powerful abilities that scale directly with level upgrades. Secondary utility pets like Diggy and Frosty should follow, while low-impact options such as L.A.S.S.I and the Mighty Yak should be left at level 1 to save Dark Elixir for hero upgrades.

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Core Priority Pets to Max First

These three companions provide the largest performance boosts in Town Hall 14 through Town Hall 16 attacks:

Spirit Fox (Town Hall 16, Pet House Level 9): The Spirit Fox is the strongest pet in the game. It periodically turns itself and its paired hero invisible, causing defenses like the Monolith and Single-Target Inferno Towers to lose targeting entirely. Pairing it with the Royal Champion allows her to clear heavy defensive pockets safely. Upgrading the Fox increases the duration of the invisibility cloak and shortens downtime.
Unicorn (Town Hall 14, Pet House Level 4): The Unicorn functions as a dedicated ground Healer that does not trigger Seeking Air Mines. It is the premier choice for the Archer Queen during Queen Charges. Upgrading the Unicorn directly raises its heal-per-second output, which is essential for keeping your Queen alive under sustained point defense fire.
Phoenix (Town Hall 15, Pet House Level 8): When its assigned hero takes fatal damage, the Phoenix hatches and grants that hero temporary invulnerability. This bought time allows a Barbarian King to finish core targets or destroy Town Hall compartments. Leveling up the Phoenix extends this invulnerability shield.

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Secondary Utility Pets

Once your core trio is upgraded, focus on companions that provide crowd control:

Diggy (Town Hall 15, Pet House Level 6): Diggy travels underground alongside its hero and stuns targeted defensive structures on hit. This stun interrupts high-damage beams and resets defense attacks. Diggy pairs effectively with the Royal Champion or Grand Warden. Upgrading Diggy increases its stun duration, damage, and hit points.
Frosty (Town Hall 15, Pet House Level 7): Frosty slows down defending buildings and Clan Castle troops with ranged attacks while continuously spawning Frost Mites to distract point defenses. Frosty pairs well with the Grand Warden. Upgrades improve Frosty's durability and the health of the Frost Mites.

Pet Upgrade Comparison

Pet	Unlock Town Hall	Preferred Hero	Primary Upgrade Benefit
Spirit Fox	TH16 (Pet House Lv 9)	Royal Champion	Longer hero invisibility uptime
Unicorn	TH14 (Pet House Lv 4)	Archer Queen	Increased heal-per-second
Phoenix	TH15 (Pet House Lv 8)	Barbarian King	Longer invulnerability duration
Diggy	TH15 (Pet House Lv 6)	Royal Champion / Grand Warden	Extended defense stun duration
Frosty	TH15 (Pet House Lv 7)	Grand Warden	Higher Frost Mite health and slow output

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Pets to Delay or Avoid Upgrading

Certain pets offer situational benefits or have been outclassed by newer options:

Angry Jelly (Town Hall 16, Pet House Level 10): Forces its assigned hero to target defenses exclusively for a set time at the start of battle. It works in specialized smash attacks with the Grand Warden, but it is an expensive luxury upgrade compared to the Spirit Fox.
Electro Owl (Town Hall 14, Pet House Level 2): Provides chained lightning attacks to support air armies like Hydra or Electro Dragons. Its low health makes it vulnerable to Air Bombs, reducing its effectiveness at Town Hall 15 and 16.
L.A.S.S.I (Town Hall 14, Pet House Level 1): Deals single-target damage over walls but lacks unique abilities, crowd control, or survivability. Diggy and Spirit Fox outperform L.A.S.S.I in every role, making it an inefficient use of Dark Elixir.
Mighty Yak (Town Hall 14, Pet House Level 3): Originally designed to bust walls for the Barbarian King, the Yak has been largely replaced by the King's Giant Gauntlet equipment and Root Riders. Its low attack speed makes it a poor candidate for upgrades.

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Recommended Pet House Progression Order

Upgrading the Pet House pauses pet research unless you complete the upgrade instantly with a Book of Building or Hammer of Building. Follow this sequence across Town Hall levels:

Town Hall 14: Upgrade the Pet House straight to Level 4 to unlock the Unicorn. Maximize the Unicorn's levels immediately, skipping L.A.S.S.I, the Electro Owl, and the Mighty Yak.
Town Hall 15: Take the Pet House to Level 6 to unlock Diggy, then push to Level 8 for the Phoenix. Focus your lab time on leveling the Phoenix and Diggy.
Town Hall 16: Immediately upgrade the Pet House to Level 9 to unlock the Spirit Fox, and take it directly to its maximum level before considering situational options like the Angry Jelly.