# SmartTub vs Koi Feeder

The clearest difference is rating: SmartTub at 4.7 against Koi Feeder's 3.0. SmartTub also leads on ads (none vs shown) and update cadence (every 5 months vs every 19 months). Koi Feeder's advantage is in-app purchases (none vs 1) and review sentiment (100% vs 71%). On price and device support there is nothing between them.

Both are free to download. SmartTub sells 1 one-off in-app purchase. Koi Feeder asks for nothing beyond the download.

SmartTub holds the better App Store score, 4.7 against 3.0. That said, the two scores are not equally well evidenced: SmartTub has 13 ratings behind it against 2, so its average is the more settled of the two. Written reviews complicate that: 71% of SmartTub's written reviews are positive against 100% of Koi Feeder's, so the app with the better star average is not the one people write more warmly about.

SmartTub ships an update every 5 months, Koi Feeder every 19 months. The most recent releases landed on November 6, 2026 and November 2, 2026 respectively.

## The numbers

| Metric | SmartTub | Koi Feeder |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.7 (13 ratings)](https://appshunter.io/ios/app/smarttub/id435173941/reviews)** | [3.0 (2 ratings)](https://appshunter.io/ios/app/koi-feeder/id1325380896/reviews) |
| Number of ratings | **13** | 2 |
| Positive reviews | 70.5% of reviews | **100.0% of reviews** |
| In-app purchases | Yes | **No** |
| Ads | **No** | Yes |
| Update frequency | **Every 5 months** | Every 19 months |
| Monetization | Free with in-app purchases | **Ad-supported** |
| Size | 77 MB | 67 MB |
| Requires iOS | 16.6 | **12.0** |
| Devices | iPhone, iPad, Apple Watch | iPhone, iPad, iPod |
| Age rating | 4+ | 4+ |
| Developer | [sorakaze Inc.](https://appshunter.io/developer/1046448101) | [kume toru](https://appshunter.io/developer/731695033) |

## What reviewers say

### SmartTub

[App page](https://appshunter.io/ios/app/smarttub/id435173941)

Experience a playful virtual bath with floating ducks. Interact with them by tilting your device, shaking to add more, flicking them around, or tapping to hear them quack. Enjoy a simple, interactive entertainment experience.

**Highlights:** Tilt to move ducks, Shake to add ducks, Flick ducks, Tap ducks to quack, Force Touch on Apple Watch to reset

**Features:** Family Sharing, Apple Watch app, iMessage stickers

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Extension Pack | $1.99 | one-time |

**What reviewers like**

- 🦆 Cute rubber ducks
- 😌 Relaxing and calming
- 🧸 Good for children
- ✨ Simple and fun
- 💖 Highly recommended

**What reviewers complain about**

- 🤷‍♀️ Lacks clear purpose
- 🥱 Becomes boring quickly
- 💸 In-app purchase expensive
- 🖱️ Limited interaction
- ❓ Confusing controls

**Reported bugs**

- Widget not working
- App not launching on Apple Watch SE
- App icon not appearing on screen

**Requested features**

- Add more toys and variations
- Implement a delete duck feature
- Add different colored ducks
- Allow water to react to touch
- Add a ripple effect


### Koi Feeder

[App page](https://appshunter.io/ios/app/koi-feeder/id1325380896)

Interact with digital koi by feeding them. Enjoy a simple, relaxing experience designed to be played with.

**Highlights:** Feed digital koi, Interact with koi, Relaxing gameplay, Simple interface

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is SmartTub free?

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

### Is Koi Feeder free?

Koi Feeder is free to download, with no in-app purchases.

### Which has better reviews, SmartTub or Koi Feeder?

SmartTub is rated higher. SmartTub averages 4.7 out of 5 from 13 ratings, while Koi Feeder averages 3.0 from 2 ratings.

### Do SmartTub or Koi Feeder have ads?

Koi Feeder shows ads; SmartTub does not.

### Which is updated more often, SmartTub or Koi Feeder?

SmartTub ships an update every 5 months, and Koi Feeder every 19 months. Most recently, SmartTub was updated on November 6, 2026 and Koi Feeder on November 2, 2026.

---

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