# RYUKIN — Gracefully Fluttering Goldfish

> Virtual goldfish aquarium with interactive fish and customizable settings. (iPhone/iPad app by Masataka Hakozaki.)

- Source: https://appshunter.io/ios/app/ryukin/id6471839445 (this page in markdown: same URL + `.md`)
- Developer: [Masataka Hakozaki](https://appshunter.io/developer/323346554)
- Category: Entertainment, Health & Fitness
- Price: $3.49 with in-app purchases
- Rating: 4.90/5 from 60 App Store ratings · 99 written reviews indexed
- Age rating: 4+
- Requires: iOS 16.0 · 225 MB
- Languages: Russian, Hindi, Vietnamese, American English, European Spanish, Italian, Korean, German (Germany), Polish, European Portuguese and 5 more
- Released: 2024-03-12
- Data updated: 2026-08-31
- Monetization: free with in-app purchases
- User reviews in markdown: https://appshunter.io/ios/app/ryukin/id6471839445/reviews.md

## What is RYUKIN?

～ Gracefully Fluttering Goldfish ～
Goldfish glide gracefully through crystal-clear water, their fins fluttering gently as they swim. Their charming gestures and soft, delicate fin movements have been carefully recreated. Enjoy the beauty of goldfish anytime, anywhere — without the need for water changes or feeding.


App Highlights
- Fish respond to your touch and follow your finger
- Customize tank shape, background color, and floating objects
- Soothing water sounds and clear, refreshing visuals
- "Cat & Baby Mode" for safe play with kittens and toddlers
- Sleep timer for relaxing bedtime use
- Play your favorite music while watching the aquarium
- Clock and date display
- White and black goldfish included; colorful and themed fish available via in-app purchase


Settings & Customization
- Camera options (Free position / Follow fish / Auto-rotation)
- Screen orientation
- Tilt sensitivity
- Sleep timer
- UI size
- Toggle water surface, bubbles, and other effects
- Adjust brightness, saturation, contrast, and color tone
- Quality settings (resolution and various effects)
- Volume settings (water sounds, bubble sounds)
- Clock & date options (font, position, size)


Other Features
- Fish, objects, and the water surface respond to touch and device tilt
- Fish may whimsically swim toward your finger
- Tap too much and the fish may faint!
- Feed the fish
- Adjust the size of fish and objects
- Display up to six fish at once


‥∴ Bringing the Allure of Goldfish Closer ∴‥
This app was born from a childhood dream of recreating goldfish through programming. Fifteen years after the release of the original app *Wa Kingyo*, countless refinements have been made to capture the graceful and charming nature of these fish. From the gentle movement of their fins to the way they chase and munch on food, experience the beauty and warmth that goldfish bring.


News and Support
X: @m_hakozaki
TikTok: @m_hakozaki
Instagram: @masataka.hakozaki

## Key features

- Interactive goldfish that respond to touch
- Customizable tank shape and background
- Soothing water sounds and visuals
- Cat & Baby Mode for safe interaction
- Sleep timer for bedtime use
- Play your own music
- Clock and date display

## Pricing and in-app purchases

Base price: $3.49.

**One-time purchases**

| Purchase | Price | Type |
| --- | --- | --- |
| ROBO FISH 02 | $1.99 | one-time |
| ROBO FISH 04 | $1.99 | one-time |
| ROBO FISH 06 | $1.99 | one-time |
| CALICO ORANGE/WHITE/BLACK | $1.99 | one-time |
| BLACK WHITE KITTY FISH | $1.99 | one-time |
| GHOST TRANSLUCENT | $1.99 | one-time |
| WIREFRAME RAINBOW | $0.99 | one-time |
| BLACK KITTY FISH | $1.99 | one-time |
| WHITE KITTY FISH | $1.99 | one-time |
| ROBO FISH 03 | $1.99 | one-time |
| GHOST BLACK | $1.99 | one-time |
| ROBO FISH 01 | $1.99 | one-time |
| ORANGE & WHITE KITTY FISH | $1.99 | one-time |
| RED RYUKIN | $1.99 | one-time |
| RED-WHITE RYUKIN | $1.99 | one-time |
| CALICO RED/WHITE/BLACK | $1.99 | one-time |
| ORANGE/WHITE | $1.99 | one-time |
| CALICO RED/GRAY/BLACK | $1.99 | one-time |
| YELLOW GOLD RYUKIN | $1.99 | one-time |
| RED CAP ORANDA | $1.99 | one-time |


## Chart rankings

- #43 in Top Paid · Entertainment (US App Store)

## What do users think of RYUKIN?

Overall sentiment: positive

**Pros**

- 💎 Gorgeous and lifelike fish
- 🎨 Beautiful and customizable environments
- 🎶 Soothing water sounds
- 🕰️ Useful clock feature
- 👍 Immersive and relaxing experience
- 🐱 Fun fantasy fish designs (e.g. cat-eared)

**Cons**

- 🔋 High battery consumption on max settings
- 💰 Additional fish require paid purchases
- 🌱 Lack of plant/natural decor options
- 🐟 Limited variety of standard goldfish

**Commonly reported bugs**

- Occasional crashing on high-end devices

**Most requested features**

- Ability to change fish colors
- Add more fish species (e.g. bettas, tetras)
- Implement fish breeding/growth mode
- Allow customizing fish placement in tank
- Add desktop/widget mode for always-on display

## Recent user reviews (10 of 99)

All indexed reviews: https://appshunter.io/ios/app/ryukin/id6471839445/reviews.md

### 5/5 — Best game for stress from school or work

*2026-07-18*

This game is worth all the money 💵 so calming good before bed my persian cat loves it to very calm ☺️ love this app no complaints so soothing to the mind BEST GAME EVER I love it even more cause I own a loin head goldfish and a ranchu goldfish in real life so I love it so much

### 5/5 — 귀엽고 조용하고 예뻐요 :)

*2026-04-27*

평소에도 물멍을 좋아해서 잘 사용하고 있습니다. 감사합니다.

평소 공부하거나 책을 읽을 때 앱을 사용하는 편이기에 타이머 등의 시계 외 기능 추가 / 위젯 추가 등의 계획은 없을까요?

### 5/5 — Unironically best game

*2026-04-15*

Yahhhhhhh take my money this is so great I love how beautiful the animations lighting and physics are it’s gorgeous keep up the good works

### 5/5 — 非常非常棒 希望一直坚持下去

*2026-04-09*

是忠实付费用户了 几款app又能硬控我又能硬控猫 非常棒

### 5/5 — Beautiful

*2026-04-06*

Please bring this to vision and macOS, I’d love to stare at it in bigger screen. Would be amazing if this could run as screensaver or take over macOS wallpaper. Actually when I come to think of it, on tvOS would be amazing too. It would be like showing aquarium on big screen tv.

### 5/5 — Gorgeously made

*2026-03-18*

The thought put into customization pays off well - the experience goes above and beyond for immersion; I will always keep it open as my 2nd wallpaper. I might never buy a real fish tank after this

### 5/5 — 아이패드 에어4 그래픽 깨짐

*2026-03-17*

일년째 잘 사용하고 있습니다! 최근 업뎃 이후로 에어4에서 깨짐이 발생하네요
에어4 기기 두 대로 확인을 했는데 모두 깨집니다
맥북, 아이패드 다른 기종에서는 정상작동합니다!
그리고 위젯 기능이 있으면 좋겠습니다 ㅎㅎ

**Developer response:** 불편 사항을 알려주셔서 감사합니다! 🙏
저도 일부 기종에서 화면 깨짐 현상을 확인했습니다. 최대한 빨리 수정 버전을 배포하겠습니다. 불편을 드려 죄송합니다 🙇‍♂️
위젯은 3D 표시가 허용되면 꼭 만들어보고 싶네요 ㅎㅎ

### 5/5 — wow just wow 🤩

*2026-03-03*

highly recommend this app to relax or have on ipad on background while drawing/working, dev if you're reading this please make bundles to buy the fish instead of individual purchases, awesome job 👏

### 5/5 — 非常漂亮

*2026-01-22*

模拟很逼真，几乎和真的金鱼一样

### 5/5 — Fish

*2026-01-20*

Absolutely Gorgeous! This game is better than me playing roblox sense of that update, everytime I feed them a big amount of food, I just feel bad for their lil tummy, I'm surprised how they never get full lol. 5 stars as always! Just hoping I could collect more fish in the future! :)

## Frequently asked questions about RYUKIN

### What does the RYUKIN app do?

RYUKIN is a virtual aquarium app that allows you to enjoy the beauty of gracefully fluttering goldfish anytime, anywhere. It recreates the charming gestures and delicate fin movements of real goldfish, providing a serene and visually appealing experience without the need for actual fish care.

### What are the key features of RYUKIN?

Key features include interactive goldfish that respond to touch, customizable tank shapes and backgrounds, soothing water sounds, a 'Cat & Baby Mode' for safe interaction, a sleep timer, and the ability to play your own music while watching the aquarium. You can also display up to six fish and customize their size.

### Is RYUKIN free to download and use?

The app is free to download and offers a base experience with white and black goldfish. Additional colorful and themed fish are available for purchase through in-app purchases, allowing you to expand your aquarium's variety.

### What devices is RYUKIN compatible with?

While specific OS versions are not detailed, the app is designed for mobile devices and offers various settings for screen orientation, tilt sensitivity, and UI size, suggesting compatibility with a range of smartphones and tablets.

### How can RYUKIN be used for relaxation?

The app is designed for relaxation through its soothing water sounds, clear visuals of gently swimming goldfish, and customizable ambiance. The sleep timer feature makes it ideal for use before bedtime, and the ability to play personal music further enhances its calming effect.

## Version history (last 5 releases)

### 1.14.5 — 2026-07-19

- Fixed an issue that could prevent the app from launching on macOS.
- Made minor adjustments.

### 1.14.4 — 2026-04-05

- UI fixes and improvements

### 1.14.3 — 2026-04-03

- Fixed an issue where sound would not resume after returning from the background on devices in silent mode
- Fixed an issue where background audio would stop when launching the app while the device was in silent mode
- UI fixes and improvements

### 1.14.2 — 2026-03-31

- UI fixes and improvements

### 1.14.1 — 2026-03-20

[Fixed]
- Fixed an issue where gradients did not display smoothly on certain devices
- Various minor improvements and fixes

[Added]
- Art style option: Normal / Pixel Art
- Wireframe goldfish
- Adjustable lens distortion and vignette effects

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## More apps by Masataka Hakozaki

- [Wa Kingyo - Goldfish Pond](https://appshunter.io/ios/app/wa-kingyo-goldfish-pond/id328011357)
- [Wa Kingyo LE - Goldfish Pond](https://appshunter.io/ios/app/wa-kingyo-le-goldfish-pond/id333192368)
- [PrismScope](https://appshunter.io/ios/app/prismscope/id513652520)
- [PrismScope Lite](https://appshunter.io/ios/app/prismscope-lite/id514506824)
- [GriGri3D Stereogram](https://appshunter.io/ios/app/grigri3d-stereogram/id1205203474)
- [MeltLand](https://appshunter.io/ios/app/meltland/id1361506315)

All apps by Masataka Hakozaki: https://appshunter.io/developer/323346554

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-31.*