THE BEST THINGS IN LIFE come in the smallest packages. There are certainly many divers who would agree with that sentiment, because the underwater world becomes ever more fascinating when we learn to dive slow, look close and appreciate the little things in life.
Most nudibranchs are smaller than the end of your thumb, but their gaudy colouration and kaleidoscopic patterns ensure that they are among diving’s brightest jewels. And this is treasure we can find on dives across the seven seas.
Yes, we’re just as likely to meet nudis, as they’re known to their friends, whether we dive on coral reefs or British wrecks.
They are irresistible subjects for underwater photographers, both because of their looks and also their speed! Moving at snail’s pace means that they aren’t going to outpace even the most methodical snapper.
Ironically, while most nudibranchs do have eyes, they are just tiny spots and too basic to appreciate their own stunning colouration.
Smell, using their characteristic chemo-sensory rhinophores, is probably their most important sense, especially for locating food and mates (although taste and touch, with their mouths and oral tentacles play a role too).
And these are usually the most important focal point in our pictures.

THE FIRST CHALLENGE in nudibranch photography is finding the little blighters. I can remember my excitement in finally seeing my first nudibranch while diving in the Seychelles. It had taken me years of searching – swimming far too quickly over reefs, looking in the wrong places.
Nudis aren’t distributed evenly through the oceans. There are definitely hot-spots and specific seasons where we’ll see far more than our fair share.
In the tropics, the best nudibranch destination I have visited is the Philippines, particularly around Anilao, although plenty of other places push it close.
Nudibranchs can be far more numerous in cold waters, although biodiversity is lower. On several occasions in the UK, I have dropped into the kelp to find it covered in hundreds of slugs (although usually all of them are from just a single species).
By far the best way to see nudibranchs is to dive with other nudi-hunters. Nudi diving events take place around the world, from liveaboard trips in deepest Indonesia to the popular Nudibranch Safari in Gulen, Norway. The nudi-nut sub-culture is a surprisingly vivacious branch of diving, and always keen to include new members and educate them in the ways of the slug.
Once you learn where to look, you can usually spot nudis on most ocean dives. Nudibranchs are carnivores and feast on non-moving invertebrate life, so the best way to find them is to look for their prey.
Non-moving invertebrates generally thrive in areas of water movement, which they rely on to bring their food.
So we’ve our best chance of finding nudis in areas of current, particularly pinnacles, wrecks and rubble. Often the best giveaway are their large, brightly coloured eggs ribbons, as they usually lay them close to where they are living.

THE MOST DRAMATIC angle from which to shoot nudi portraits is dead ahead, framing the slug coming towards the lens. Our aim is to have the rhinophores sharp in the foreground, framed against the colourful slug behind.
Typically vertically framed pictures work best, yet are less commonly taken. We want to position our camera right down at “eye” level for the most engaging angle, and it is usually best to wait for the nudi to crawl up onto something, so that we can compose it against a clean background.
Nudibranchs are small, so we often need to push beyond 1:1 and into the realm of super-macro for frame-filling shots. Accessory close-up lenses, such as the Subsee or Nauticam SMC, are the perfect tools. But going for such magnification means that depth of field will be razor-thin, and our focus must be precisely on the rhinophores.
The alternative angle to celebrate nudibranch beauty is from the side, to show the whole animal in an ID-style shot.
To maintain a degree of connection with the view, it is usually best to approach from a roughly three-quarters side-on position, so that the subject is still coming onto the camera slightly.
If the nudi’s pattern is mostly on its back, then I will often shoot slightly down on the subject, rather than staying at its level. When the nudi is on a particularly photogenic background, such as a colourful sponge, a clean kelp frond or the repeating pattern of a colonial bryozoan, I often try a completely top-down angle.
I will usually shoot a co-operatively positioned nudi from several angles and choose the best shot afterwards. As a rule of thumb, I find that the front-on angle works best with the “sausage-shaped” dorid nudis, while the side angle suits aeolid nudis, the ones with “many sausages on their backs”!

NUDI-NUTTERS are totally satisfied just collecting as many species as possible, but for the more photographically motivated, a great nudi should just be our starting point for a compelling underwater photo.
We can really make our nudi-snaps special by looking to incorporate some behaviour, endowing the photos with secondary interest.
Fortunately, nudibranchs are regularly up to something and, if I am honest, there have been more than a few occasions on which I have set out to shoot a portrait and ended up with behaviour as the by-catch.
Each type of nudi species has a very specific diet and they usually live on their food, so we’ll regularly catch them feeding. We will also frequently see them paired up, right side to right side, mating, or going round in circles, laying their characteristic spiralled egg ribbons. We can even find other animals hitching a ride, such as beautiful emperor shrimp.
Photographing nudibranchs is addictive. Earlier this year I judged the inaugural Nudibranch Photo Competition, a contest just for pictures of sea slugs, and it attracted almost 1000 entries!
You can see the results in the June edition of DIVER. And if you are interested in underwater photography competitions, watch this space next month, when we’ll have news you definitely won’t want to miss…

STARTER TIP
Nudibranch photos are all about showing off the subject’s natural beauty. Simple compositions, sympathetic lighting and non-distracting backgrounds are our goals.
Single-strobe front lighting is often better than twin-strobe as it reveals a little more texture and drops a tiny shadow beneath the slug, to help pop it off the background.

MID-WATER TIP
Nudibranchs come in many sizes and colours, and rather than just take natural-history images we can use them to create art.
For example, think bigger than one picture and shoot a series of close-ups of different slugs and tile these patterns together in Photoshop to create a composite of nudibranch abstracts.

ADVANCED TIP
The best nudibranch photos are really about the rest of the frame.
Search for slugs on great backgrounds, with commensal shrimps or mating. It is this secondary interest that will really elevate a nudibranch photo into something memorable.