Duo Aquarium is a $1.00 fish tank app that switches to a Desk view when you fold the iPhone Duo part-way into a tabletop position. The tank and a clock sit above the hinge, while the feeding, lighting and aquarium controls move to the half below.
Developer Kendal Slack launched the app on the App Store on October 14, and version 1.1 added native iPhone Duo support on October 24.
Duo Aquarium switches to Desk view when you fold the iPhone Duo part-way
Fold the iPhone Duo part-way into a tabletop position and Desk view starts automatically. The controls sit below the hinge, clear of the fold, and opening the phone flat brings back the full aquarium.
Desk view pairs the tank with a clock, the date and optional local weather. You can choose the clock’s position, font and format, or show just the tank.
You can switch the tank between daybreak, daylight, moonlight and reef-blue lighting, and a daily light cycle dims it in the evening. Calm music and water sound are optional, so you can also keep the tank silent.
You build the tank yourself and can share it with friends
Building the tank
- Freshwater fish such as tetras and angelfish, or reef fish such as clownfish and tangs
- Plants, corals, anemones, rocks and wood, with coral placed on live rock
- Moving water, rippling light and real 3D scanned coral that give the tank depth
You feed your fish and watch them gather. Tapping any resident or piece of scenery identifies it, and you can take a clean picture of your tank with the controls hidden.
Sharing the tank
A friend can visit your tank with a code or link and sees your fish, scenery and lighting, while their own tank stays saved. You can also place two nearby devices side by side and stretch one tank across them, so fish swim between the screens and either device can feed them.
Nearby sharing uses Wi-Fi or Bluetooth. Visiting a shared tank needs an internet connection, and hosting one requires iCloud. Sharing stays off until you enable it, and you can stop it at any time.
Duo Aquarium costs $1.00 and runs on iPhone, iPad and Mac
Home Screen and Lock Screen widgets show your tank and your last feeding. You can also set a daily feeding reminder or feed your fish through Siri and Shortcuts, and the tank is saved on your device with no ads or tracking.
The aquarium and Desk view also run on other iPhones, iPad and Mac in their own screen layouts. You need iOS 18.0 or later and 135.1 MB of free space.
