Essential Tips for Nudibranch Photography

Nudibranchs are perhaps the most photographed sea creatures of all time. They come in a wide variety of show-stopping shapes, colors and body textures that create a perfect storm for photographers of every level. But this does not mean that they are easy subjects to photograph, and even though they tend to be sluggish, bringing home high quality images can be surprisingly elusive. Every underwater photographer who strives to break away from the simple 2-dimensional ID shot knows that it is a continuous challenge to create striking nudibranch images.

Nudibranch Anatomy 101

It is extremely important to understand the anatomy of a nudibranch at even on the most basic level (as discussed below), and arming yourself with a little knowledge will help improve your images right away.

Nudibranchs, also known as slugs, are evolved mollusks. Some have lost their shells as part of evolutionary development while others have internalized their shells. Slugs are all both female and male but cannot reproduce without a mate of the same species.

Nudibranch Terminology

Nudi-Branch means Naked Gills

Aeolids – A type of nudibranch shaped a bit differently than most, as they do not have the conspicuous gills like the dorid type slugs. The hairy appendages or tufts on their back or running up the sides are called Cerata.

Cerata - The Cerata can contain nematocysts absorbed while feeding on hydroids. These nematocysts cells are stored within the Cerata and fire off with the slightest touch, defending the slug against would-be predators in the same fashion as a stinging jellyfish. The Cerata also function similarly as the gills on a Dorid and can be very colorful. The Cerata of Phylodesmius nudibranchs also produce food through photosynthesis.

Gills or Bronchial Plume - This elegant feature is located at the back of the slug and carries out the vital process of the gas exchange (breathing). There is also an anus hidden in the plumes. This area can retract quickly when the slug has been startled, so be careful when moving in for a photo. It is not uncommon to see a shrimp in the gill area feeding on the organic bio matter and keeping the slug healthy and clean.

Notum - Body of the entire slug, can be a solid color or multi colored and textured, very detailed or mundane.

Rhinophores - Are different for many types of slugs; they can be rolled, finned, bulbous or surrounded by a protective crown as with the Dendronotids. These sensory organs are located on the front of the slug and look like antennae, which are used to smell. These should be thought of as the eyes of the nudibranch (although they do not use them to see) and should be sharp in your images.

Oral Tentacles - These are two little nubs used to detect and guide food into the nudibranch’s mouth, which can be seen when a slug rears back on its haunches.

Oral Veil – This feature is more obvious with Melibe style nudis that vacuum up mysid shrimp by enlarging their hood and trapping food underneath. The mouth of other nudis, such as Felemaris, can be very colorful as well, adding another dimension to capturing their feeding behavior.

Nudibranch Photo Gear Essentials

Not all nudis are created equally. In fact, Nudibranchs are the world’s most diverse animal, so be prepared to meet this unique photography challenge. Increasing magnification can limit composition and depth of field but is essential for the smallest of the nudibranchs you will encounter.

Diopter and Adapter 

Because nudis come in all sizes, a diopter with flip adapter setup is always recommended and in some cases is a vital tool for getting the shot. The increased magnification helps for small nudis while the adapter makes it easy to flip down in front of your port.

We recommend these diopters:

• SubSee +5 Diopter

• SubSee +10 Diopter

• Nauticam SMC

Modeling Lights and Strobes

A modeling light is extremely important as it will help to illuminate your subject and allow your eye to gain a better sense of color and focus. A modeling light will also assist your camera autofocus by creating contrast – one of the elements used to lock focus. Your modeling light can also supplement and in some cases replace a strobe depending on your camera system and power of the modeling light. 

A strobe will definitely add color and sharpness to your images, and help the nudibranch stand out from the background. Remember: lighting is everything with photography and quality strobes will last for many years.

• View underwater strobes on Bluewater Photo

• View modeling and focus lights on Bluewater Photo

Nudibranch Photo Tips

Try applying the following to help you to break through to your next level of nudibranch photography.

1)  Research and know the basic anatomy of your subject. Take it a step further with Dave Behrens’ Nudibranch Behavior book.

2)  Get Low, Get Close, Shoot Up – this is macro 101; use this formula to dramatically improve your images.

3)  Compose with negative space and room to move within the frame. View UWPG’s underwater composition tutorial.

4)  Use higher shutter speeds – using you maximum flash sync shutter speed will help to keep out the ambient light.

5)  Try to photograph behavior: mating, eating and laying eggs.  This is the peak of the action for nudibranchs.

6)  Look for symmetry - nudibranchs are almost always exactly the same on each half of their bodies. Head-on images (portraits) are okay when the subject allows it.

7)  Be creative with depth of field - Pay close attention to the features of your nudi subject - while it’s important that the Rhinophores are sharp, other parts of the nudi, like the gills, can be out of focus.

8)  Take advantage of black background opportunities – If the subject is perched up high, create a black background. But be careful of slugs with black Rhinophores as they will easily blend in with the background.

9)  Experiment with best settings - A slight increase or decrease of your f-stop can bring out subtle details in the texture of your subject.

Nembrotha lineota. Get low, get close and shoot up. Use negative space and be sure your subject's Rhinophores are sharp.

Nembrotha chamberlaini. If there is an anomaly of some sorts that sets your subject apart for the norm be sure that this anomaly is the center of the viewers’ attention.

Chromodoris leopardis. Laying eggs is always a very interesting behavior to capture. The eggs are often brightly colored and textured. If eggs are found alone, inspect them, as other nudibranchs often feed on them.

Showing nudibranch symmetry works well, like with this shot of a Nebrotha kuberyani. I particularly like to shoot these guys because of their interesting facial features, texture and vibrant colors.

Glossodoris cincta. These larger nudis will fill your frame easily with or without a diopter. Paying close attention to the camber of your subject's Rhinophores will help with head-on composition. The gills of the cincta actually vibrate as they move and are fun to watch.

Mimicry is another behavior that an entire article could be written about, especially with these amazing Lobiger sp. Sap suckers live on algae that resembles green grapes. This image was shot in very shallow water in broad daylight. Using a high shutter speed will enable you to control the incoming light, even on the sunniest days. When a subject is tall, try turning your camera to the portrait position.

Miamira tenue aka Ceratasoma tenue can grow to impressive sizes. Some are large enough to sport accessories like this emperor shrimp that lives a symbiotic lifestyle with its host. Keeping its hosts gills cleaned and rummaging for food as the nudi moves along the substrate is priority number 1 for the shrimp, and getting photos of them on the nudi are great behavioral images.

Using a quality diopter of +10 or greater will dramatically increase the size of very small subjects and allow you to fill the frame with very little cropping. These Castosiella kuroshimae are miniscule and nearly impossible to detect. Look on small algae on sandy dive sites.

Extreme depth of field isn’t always necessary, but on a larger subject its hard to resist, especially when one is as colorful as this Hypseledoris. Backing away from your subject is an easy way to slightly increase your DOF when working with nudibranchs.

In Conclusion

Be sure to practice these simple steps as discussed above to help improve your chances at shooting your next jaw dropping slug image no matter where you are or what ever system you are using. Take your time and remember to always have fun!

Further Reading

• UWPG's Guide to Nudibranchs

• Underwater Composition with the Rule of Thirds

• Tips for Artistic Macro Photography

Other Articles by Mike Bartick

• Critters in Ambon Photo Essay

• Photographer's Guide to Muck Diving

• Jupiter by Surprise: Sharks, Groupers & Macro in Florida