# Flutter vs Zen Koi 2

The clearest difference is update cadence: Flutter at every 8 days against Zen Koi 2's monthly. Zen Koi 2's advantage is ratings volume (30K vs 4.9K). On price, rating, review sentiment and ads there is nothing between them.

Both are free to download. Flutter sells 10 one-off in-app purchases and Zen Koi 2 sells 10 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.

On the App Store both sit at effectively the same score — 4.7 for Flutter against 4.8 for Zen Koi 2. That said, the two scores are not equally well evidenced: Zen Koi 2 has 30K ratings behind it against 4.9K, so its average is the more settled of the two. Written reviews are what separate them: 73% of Flutter's written reviews are positive against 71% of Zen Koi 2's.

Flutter ships an update every 8 days, Zen Koi 2 monthly. Both last shipped on November 10, 2026.

## The numbers

| Metric | Flutter | Zen Koi 2 |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.7 (4.9K ratings)](https://appshunter.io/ios/app/flutter-butterfly-sanctuary/id564007552/reviews) | **[4.8 (30K ratings)](https://appshunter.io/ios/app/zen-koi-2/id1280254438/reviews)** |
| Number of ratings | 4.9K | **30K** |
| Positive reviews | **72.7% of reviews** | 71.4% of reviews |
| In-app purchases | Yes | Yes |
| Ads | Yes | Yes |
| Update frequency | **Every 8 days** | Monthly |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Size | 539 MB | 153 MB |
| Requires iOS | 15.0 | 15.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | +4 | 4+ |
| Developer | [Runaway](https://appshunter.io/developer/1042800793) | [LandShark Games Pte. Ltd.](https://appshunter.io/developer/635142101) |

## What reviewers say

### Flutter

[App page](https://appshunter.io/ios/app/flutter-butterfly-sanctuary/id564007552)

Create a vibrant rainforest sanctuary by collecting and nurturing hundreds of real butterfly species. Watch them grow through their life cycle, learn fascinating facts, and expand your magical forest with beautiful decorations. Enjoy relaxing gameplay with a calming soundtrack and discover new species through missions and events.

**Highlights:** Collect 400+ real butterfly species, Nurture butterflies through their life cycle, Expand and decorate your forest sanctuary, Engage in missions and limited-time events, Relaxing gameplay with peaceful ambiance

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases (10)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Beetle Bank | $0.99 | one-time |
| 50 Flutterbucks | $1.99 | one-time |
| Amazing Value Pack | $1.99 | one-time |
| Starter Park 001 | $2.99 | one-time |
| Starter Pack B | $4.99 | one-time |
| 130 Flutterbucks | $4.99 | one-time |
| Nectar Booster | $4.99 | one-time |
| Spirit Booster | $4.99 | one-time |
| 275 Flutterbucks | $9.99 | one-time |
| 700 Flutterbucks | $24.99 | one-time |

**What reviewers like**

- 🦋 Beautiful and relaxing game
- 👍 Informative and educational
- 🎨 Gorgeous graphics and animations
- 🎶 Calming music and ambiance

**What reviewers complain about**

- 🐛 Frequent crashes and bugs
- 💰 Expensive in-app purchases and expansions
- ⏱️ Slow progression and long wait times
- 🔒 Requires constant internet connection

**Reported bugs**

- Game resets progress after updates
- Inability to access Flutterpedia and achievements
- Inconsistent performance and freezing issues

**Requested features**

- Offline mode
- Ability to sell or remove unwanted butterflies
- More interactive events and mini-games
- Expanded forest and storage space


### Zen Koi 2

[App page](https://appshunter.io/ios/app/zen-koi-2/id1280254438)

Nurture and breed vibrant koi, guiding them through a serene journey to transform into majestic dragons. Customize your underwater sanctuary and create unique constellations in a breathtaking celestial realm.

**Highlights:** Breed and nurture koi, Transform koi into dragons, Explore the Dragon Realm, Craft and share constellations, Customize personal aquarium, Compete on leaderboards

**Features:** Vision Pro support

**In-app purchases (10)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Small handful of Pearls | $1.99 | one-time |
| Starter Pack | $1.99 | one-time |
| Value Pack | $1.99 | one-time |
| Offer Pack | $1.99 | one-time |
| Shodo Pack | $2.79 | one-time |
| Fun Pack | $3.99 | one-time |
| Handful of Pearls | $4.99 | one-time |
| Nice Pack | $8.99 | one-time |
| Bag of Pearls | $9.99 | one-time |
| Tsuru Pack | $9.99 | one-time |

**What reviewers like**

- 🌊 Relaxing and calming game
- 🐉 Ability to play as dragons
- 🎨 Beautiful graphics and animations
- 🎶 Soothing music
- 🔓 No intrusive ads

**What reviewers complain about**

- 🕰️ Slow progression and high costs for new koi slots
- 🐟 Repetitive prey-catching gameplay
- 🔌 Connectivity issues and loading problems
- 🤖 Unsatisfying dragon gameplay

**Reported bugs**

- Saved progress being lost or not loading properly
- Glitches with dragon appearances

**Requested features**

- Offline play mode
- More variety in pond environments and prey
- Ability to interact with and customize dragons
- Easier way to complete collections
- Improved friend integration and trading


## Frequently asked questions

### Is Flutter free?

Flutter is free to download, with in-app purchases available.

### Is Zen Koi 2 free?

Zen Koi 2 is free to download, with in-app purchases available.

### Which has better reviews, Flutter or Zen Koi 2?

Zen Koi 2 is rated higher. Flutter averages 4.7 out of 5 from 4.9K ratings, while Zen Koi 2 averages 4.8 from 30K ratings.

### Do Flutter or Zen Koi 2 have ads?

Both Flutter and Zen Koi 2 show ads.

### Which is updated more often, Flutter or Zen Koi 2?

Flutter ships an update every 8 days, and Zen Koi 2 monthly. Most recently, Flutter was updated on November 10, 2026 and Zen Koi 2 on November 10, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*