# Flutter vs Zen Koi Classic

The clearest difference is update cadence: Flutter at every 8 days against Zen Koi Classic's every 3 months. Zen Koi Classic's advantage is review sentiment (86% vs 73%). On price, rating, ratings volume and ads there is nothing between them.

Both are free to download. Flutter sells 10 one-off in-app purchases and Zen Koi Classic 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 4.7 for Zen Koi Classic. Both are backed by a comparable volume of ratings — 4.9K and 2.1K respectively. Written reviews are what separate them: 73% of Flutter's written reviews are positive against 86% of Zen Koi Classic's.

Flutter ships an update every 8 days, Zen Koi Classic every 3 months. Both last shipped on November 11, 2026.

## The numbers

| Metric | Flutter | Zen Koi Classic |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.7 (4.9K ratings)](https://appshunter.io/ios/app/flutter-butterfly-sanctuary/id564007552/reviews)** | [4.7 (2.1K ratings)](https://appshunter.io/ios/app/zen-koi-classic/id896575207/reviews) |
| Number of ratings | **4.9K** | 2.1K |
| Positive reviews | 72.7% of reviews | **85.6% of reviews** |
| In-app purchases | Yes | Yes |
| Ads | Yes | Yes |
| Update frequency | **Every 8 days** | Every 3 months |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Size | 539 MB | 128 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 Classic

[App page](https://appshunter.io/ios/app/zen-koi-classic/id896575207)

Nurture and collect vibrant Koi fish in a serene underwater world. Watch them grow, evolve into majestic dragons, and discover hundreds of unique varieties. Share your collection with friends and enjoy a calming, visually stunning experience.

**Highlights:** Breed and collect hundreds of unique Koi varieties, Watch Koi evolve into majestic dragons, Soothing music and mesmerizing visuals, Intuitive single-touch controls, Share and gift Koi with friends, Limited edition rewards for collectors

**Features:** Vision Pro support

**In-app purchases (10)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Starter Pack | $1.99 | one-time |
| Small Handful of pearls | $1.99 | one-time |
| Handful of pearls | $4.99 | one-time |
| Hasu Pack | $4.99 | one-time |
| Bag of pearls | $9.99 | one-time |
| Tenshi Pack | $9.99 | one-time |
| Splatto Pack | $9.99 | one-time |
| Yajiri Pack | $9.99 | one-time |
| Monkī Pack | $19.99 | one-time |
| Nami Pack | $19.99 | one-time |

**What reviewers like**

- 🌊 Relaxing and calming gameplay
- 🎨 Beautiful and intricate koi designs
- 🐉 Enjoyment of breeding and evolving koi into dragons
- 🕰️ Great way to pass time and de-stress
- 🎶 Soothing and pleasant background music

**What reviewers complain about**

- 💰 Difficulty earning pearls without in-app purchases
- 🔒 Limited number of koi/egg slots without spending pearls
- 🐛 Occasional crashes and bugs after updates
- 🆕 Concerns about losing progress after updates
- 📺 Disruptive full-screen ads

**Reported bugs**

- Koi and dragon progress lost after updates
- Inconsistent koi movement and speed issues
- Ads causing frequent crashes or freezes

**Requested features**

- Ability to play as or interact with dragons
- More koi slots or alternative ways to expand pond
- Easier ways to earn pearls without watching ads
- Ability to name or customize koi and dragons
- Zoom out feature to see full pond layout


## Frequently asked questions

### Is Flutter free?

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

### Is Zen Koi Classic free?

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

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

Flutter is rated higher. Flutter averages 4.7 out of 5 from 4.9K ratings, while Zen Koi Classic averages 4.7 from 2.1K ratings.

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

Both Flutter and Zen Koi Classic show ads.

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

Flutter ships an update every 8 days, and Zen Koi Classic every 3 months. Most recently, Flutter was updated on November 11, 2026 and Zen Koi Classic on November 11, 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.*