It’s said that the best things come in small packages, and plenty of divers would agree. The underwater world becomes ever more fascinating when you learn to dive slowly, look closely and appreciate the little things. Nudibranchs and sea slugs are mostly smaller than the end of your thumb, but their intense coloration makes them the ocean’s brightest jewels. (Look for the social media post doing the rounds comparing their patterns and David Bowie’s costumes!)

Nudibranchs are a photographic treasure you can find all around the world, as common in chilly waters as they are in the tropics. They are irresistible both because of their looks and their speed—these gastropod mollusks move at a snail’s pace, which means they aren’t going to outrun even the most methodical shooter. However, we still need to focus on the details to create standout images.

TIP 1: SLUG SPOTTING

The first challenge of nudibranch photography is finding one. Yes, they are found the world over, but they are not evenly distributed. There are hotspots and specific seasons when they’ll seem to be everywhere, and other times and places where you won’t find one however hard you look. In the tropics, the best nudi destination I have visited is the Philippines, particularly around Anilao. In cold water, Norway at the end of winter can be incredible, with hundreds in the fjords, although with far less variety.

The easiest way to find them is to dive with expert nudi hunters. An alternative is to join nudibranch diving events, which take place around the world from liveaboards trips in the tropics to local dive weekends. But it’s much more satisfying to photograph nudibranchs you find for yourself.

Nudibranchs are carnivores and feast on stationary invertebrate life bigger than they; the best way to find them is to look for their prey. These invertebrates thrive in areas of water movement, which they rely on for food. As a general rule, the best place to find nudis is in areas exposed to current, particularly pinnacles, wrecks and rubble. Often the giveaway is their large, eye-catching eggs ribbons, as they usually lay them close by. Individual nudibranch species have very specific diets, so once you know what species are common in an area and learn what they eat, you can find them more regularly.

TIP 2: ANGLES OF ATTACK

If you want to inject your slug shots with impact, there’s one angle that guarantees dramatic images: dead ahead, framing the slug coming toward the lens. The aim is to have a pair of razor-sharp rhinophores as a focal point, framed against the colorful slug behind. The composition looks particularly good when photographed as a vertical frame but also works well— and is easier to take—as a horizontal. The challenge is to get your camera right down to eye level; it’s usually best to wait for the nudi to crawl up onto something, so you can compose it against a clean background.

Most nudibranchs are small, so we often need to push beyond 1:1 and into the realm of super macro for frame-filling shots. The popular close-up lenses that most photographers already own are the perfect tools. However, when you work at these higher magnifications, your depth of field will be razor-thin, meaning you have to precisely focus on the rhinophores. I usually shoot a series of frames to be sure of one that is spot-on. I don’t worry if the rest of the nudibranch is out of focus—in fact the photo can look striking the more blurred the body is, as long as those rhinophores are pin-sharp.

Alternative angles that can work well are side-on and top-down, revealing the patterns of the whole animal. As a rough rule of thumb, if the nudi is sausage-shaped (dorids) it often looks good from above, while if it has sausages on its back (aeolids) it looks better from the side. If the slug is on a particularly photogenic background, I might shoot a shallow depth of field to blur the color. If it’s on an invertebrate with a pleasing pattern, I try to keep the camera parallel to the subject and stop down the lens to keep everything in focus.

While nudi nuts are motivated by collecting as many species as possible, a photographer’s quest should be a standout image. Incorporating some behavior is an ideal way to make your shots special, endowing your photos with additional interest. Fortunately, although they live slowly, they are usually up to something, and if you leave them unmolested you will regularly capture behavior by accident. Nudibranchs spend a lot of time eating slowly; while it can be hard to see this underwater, it is often captured in photos.

Related:

• Three Unusual Macro Photography Tips
• 10 Amazing Nudibranch Photos
• How to Photograph a Clownfish
• Common Mistakes Underwater Photographers Make—and How to Fix Them