Deep sea imagery is the quietest thing in the underwater category. Almost no colour, almost no light, a single shape emerging from black water. It is also, for a phone, close to ideal — and for reasons that have nothing to do with how dramatic sharks look.
Here is why it works, and how to choose between the calm end and the loud end of it.
Black water is the best possible lock screen background
An OLED iPhone switches individual pixels off to make black, rather than dimming them. So a deep sea image is not a dark picture on a lit screen. Most of the screen is genuinely off, and the subject appears to float on nothing.
That gives you three things at once. The white clock is perfectly legible with no adjustment. The subject reads at a glance because there is nothing else in the frame. And the wallpaper costs almost nothing in power, which matters if you use the always-on display on a Pro model, since the image is on screen for much of the day.
Very little else in wallpaper photography gives you all three.
Shark art versus deep sea photography
They are treated as the same category and they behave differently.
A shark composition is a portrait. One large subject, a clear silhouette, high contrast, usually approaching the camera. It reads instantly, the depth effect can lift it, and it is genuinely striking.
It is also a lot to look at repeatedly. A large predator filling the frame is not a restful thing to see every time you check the time, and this is the most common reason a shark wallpaper gets replaced after a week or two.
Deep sea photography without a headline subject — a shaft of light in dark water, particles drifting, a distant silhouette — is far quieter. Less impressive in a gallery, much easier to live with.
Both are worth having. They belong on different screens.
Where each one belongs
The lock screen editor lets you build more than one screen and attach each to a Focus, which is the natural home for this split.
The quiet deep water scene works as the default screen and as a Sleep Focus screen. Dark, low contrast, nothing demanding attention at the hour when you least want it.
The shark works on a Do Not Disturb or a weekend screen, where you see it occasionally and the impact is the point rather than the burden.
Check the blacks before you commit
This is the one category where file quality is immediately obvious, because most of the frame is a single dark tone with nothing to hide behind. A compressed or upscaled file lifts the shadows to grey and breaks the gradient from the subject into the water, and both faults are invisible at full brightness and glaring at the low brightness you actually use at night. Set it, then look at it once in a dark room. If the water is grey rather than black, or if you can see rings and steps in the fade, find a larger original.
The light shaft is the underrated composition
If you only take one recommendation from this, take this one.
A shaft of sunlight cutting down through dark water, with no animal in it at all, is the most useful image in the whole underwater category. It gives you a bright element to anchor the composition, a near-black frame around it, and a natural vertical line that fits a portrait screen without cropping.
It also solves the clock problem by accident. The light enters at the top and widens downward, so the brightest part of the frame is usually in the middle, leaving the upper corners dark where the time sits.
And it has no subject, which sounds like a weakness and is the reason it lasts. There is nothing to get tired of. You register the shape, the phone unlocks, and you have not been asked to look at a predator.
The variant with particles drifting through the beam is better still on a live version, because the motion is continuous and looks correct at any frozen moment.
Live versions and what actually plays
Deep sea suits motion better than most subjects, because the natural movement is slow: particles drifting, a shape passing, light shifting through water.
Set expectations on what iOS does. Nothing on the lock screen loops continuously in the background. Motion happens at moments, on wake, on unlock, on tilt, and then it holds. On Pro models from iPhone 14 onward, the always-on display shows a dimmed static version while the phone is idle.
That constraint suits slow ambient motion and punishes anything with an event in it. Drifting particles look right at any frozen moment. A shark caught halfway across the frame does not.
The home screen has never animated on iPhone, on any version.
Pairing the home screen
Near-black is the best home screen background there is: maximum contrast against the icons, nothing competing with the labels, and almost no power cost on OLED.
Blur the lock screen image in the Home Screen panel under Customise and you get a near-black field with a hint of the subject. If you want the shape visible, use a crop that puts it low, under the icon grid rather than behind it.
Quick answers
Why does my dark wallpaper look grey rather than black?
Either the file has lifted blacks from compression, or the display is showing it at a brightness where the difference is visible. Check it in a dark room, which is the honest test.
Does a near-black wallpaper really save power?
On an OLED iPhone, yes, because unlit pixels draw none. On an older LCD iPhone the backlight is on regardless, so the image makes no difference and only brightness does.
Will the depth effect lift a shark?
Usually, if the background is plain water and the silhouette is clear. It will not work on murky scenes where the subject fades into the background, which is most of the atmospheric ones.
Is this a good choice for the always-on display?
The best in the category. The always-on state dims everything, and an image that is mostly unlit already loses almost nothing.
Where to get it
Aquarium 3D: Live Wallpapers has deep water and open ocean scenes alongside the reef ones, in both still and live form, previewed at full size in a phone-shaped frame so you can check the blacks before saving.
Take two: a quiet one for every day and a striking one for a Focus screen. They are not competing for the same job.