PC FISH breeding interface Frostblue Sunfish plus Banggai Starfin producing Rare Golden Butterflyfish
EDITOR'S PICK · BREEDING

Complete Breeding Guide: Rare & Mythic Fish

By PC FISH Guide TeamAug 26, 202612 min read

Breeding is the heart of PC FISH: Taskbar Aquarium. By pairing the right fish, you can produce offspring of higher rarity tiers — from Common all the way up to the coveted Mythic tier. This guide breaks down the breeding mechanics, explains the heart affinity system, and provides proven combos for every rarity tier.

Key Insight: A Common + Uncommon pair can produce a Rare offspring (e.g., Frostblue Sunfish + Banggai Starfin → Golden Butterflyfish). Rarity jumps are possible but depend on affinity and luck.

Table of Contents

1. How Breeding Works

To breed fish, open the breeding menu and select two parent fish from your collection. The game will calculate a potential offspring based on the parents' species, rarity, star rating, and their mutual heart affinity. After a short breeding period, you'll receive the offspring.

  1. 1

    Select two parent fish

    Choose from fish in your aquarium. Each fish shows its rarity, star rating and current breeding count.

  2. 2

    Check heart affinity

    The heart icon shows compatibility. Higher affinity means better chance of rare offspring and higher star ratings.

  3. 3

    Wait for breeding to complete

    Breeding takes a short time. The offspring appears in your aquarium when ready.

  4. 4

    Collect and repeat

    Keep the offspring for collection or breeding stock, or export duplicates to Steam for trading.

2. Rarity Tiers Explained

PC FISH features five rarity tiers, each with its own color coding and value. Within each tier, fish also have a 1-5 star rating that affects currency generation and breeding potential.

RarityColorDescriptionMarket Value
CommonGrayStarter fish, easy to acquireLow
UncommonGreenSlightly rare, decent incomeLow-Medium
RareBlueNotable species, good incomeMedium
LegendaryPurpleVery rare, high incomeHigh
MythicGoldExtremely rare, top tierVery High

3. Heart Affinity System

When selecting two fish to breed, you'll see a heart indicator representing their affinity (compatibility). Higher affinity directly improves breeding outcomes:

  • ♥♥♥High affinity: Best chance of rarity upgrade, higher star ratings, and new variants.
  • ♥♥Medium affinity: Decent results, occasional rarity upgrades.
  • Low affinity: Offspring likely matches lower parent rarity, fewer variants.

Tip: Fish from the same family or habitat tend to have higher affinity. Experiment with different pairs to discover high-affinity combos.

4. Best Breeding Combos

Based on community testing and in-game examples, here are proven breeding combos that produce higher-rarity offspring:

Common+UncommonRare

Frostblue Sunfish + Banggai Starfin → Golden Butterflyfish

A well-documented combo from the game's breeding interface. A Common paired with an Uncommon can jump to Rare with sufficient affinity.

Rare+RareLegendary

Rare + Rare (same family) → Legendary

Pairing two Rare fish from the same family with high affinity has the best chance of producing a Legendary offspring.

Legendary+LegendaryMythic

Legendary + Legendary (max affinity) → Mythic

The only reliable path to Mythic fish. Both parents must be high-star Legendary with maximum heart affinity. Expect many attempts.

Common+CommonUncommon

Common + Common (same species) → Uncommon / higher stars

Breeding two of the same Common species is the fastest way to raise star ratings and unlock Uncommon variants early game.

5. Unlocking Variants

Each fish species has multiple visual variants. Your fish detail panel shows a variant completion percentage (e.g., "Variant: 40%"). Breeding is the primary way to discover new variants. The Variant Mastery achievement requires reaching 100% variant collection.

PC FISH fish detail panel showing variant completion percentage and star rating

The fish detail panel tracks variant progress and breeding count for each species.

  • Breed the same species repeatedly to roll for new color/pattern variants.
  • Higher star rating parents have a better chance of producing unseen variants.
  • Cross-species breeding can sometimes produce variant forms of either parent species.

6. Chasing Mythic Fish

Mythic fish are the ultimate breeding goal. They are extremely rare, generate the highest passive income, and command premium prices on the Steam Community Market. Here's a strategy for chasing them:

  1. 1

    Build a Legendary breeding stock

    You'll need at least two high-star (4-5 star) Legendary fish of compatible species. This takes significant time and currency.

  2. 2

    Maximize affinity

    Only attempt Mythic breeding when both fish show maximum heart affinity. Low affinity attempts waste your Legendary breeders.

  3. 3

    Breed repeatedly

    Mythic offspring are rare even with perfect parents. Expect 10-50+ attempts per Mythic fish. Keep breeding and don't get discouraged.

  4. 4

    Decide: keep or sell

    Mythic fish are valuable. Keep one for collection and passive income; export duplicates to Steam for significant wallet funds.

Warning: Never export your only Legendary breeder to Steam. Always maintain a breeding pair of each high-rarity species before selling duplicates.

7. Breeding Tips & Efficiency

Tip 1: Breed during active play sessions so you can immediately start the next breeding pair when one finishes.

Tip 2: Keep a "breeding stock" tank separate from your display fish so you always have pairs ready.

Tip 3: Use the Merge system to combine duplicate fish and free up aquarium space for more breeders.

Tip 4: Check the Collect encyclopedia before breeding — prioritize species with low variant completion.