Diving in the Dark

Goatfish in its night clothes. Goatfish in its night clothes.
Lighting up the detail of the reef at night with an underwater light reveals everything in a full spectrum of vibrant colour that you would never see in daylight filtered blue as it passes through the water. At the same time, many creatures of the reef are nocturnal. They include predators such as white-tip reef sharks and moray eels that are active, hunting at night. Crinoids such as feather stars and basket stars creep from their daytime hiding places to feed on plankton.
An Octopus hunting out on the sandy seabed at night. An Octopus hunting out on the sandy seabed at night.
It's at this time that the coral polyps come to life, protruding out from their hard coral structure, waving their arms.
A marble ray feeding in the sand at night in the Maldives A marble ray feeding in the sand at night in the Maldives and oblivious to the presence of divers.
Strangely, many of the more timid animals seem less aware of the presence of divers at night and seem mesmerized by a diver’s light. Other creatures can take advantage of this to make their hunting easier. Some of the most commonly encountered animals include rays feeding and turtles browsing, goatfish probing for their supper in the sand and crabs and lobsters parading out in the open. It’s also at night that the fascinating octopus stalks its supper, a meal of shellfish. Some  animals are considered special quarries for divers. These include the flashlight fish of the Indo-Pacific region, the rosy-lipped batfish in the American Pacific, and Spanish dancers - huge nudibranchs that are usually coloured bright red or pink and carry shrimps on their backs. Mandarin fish too  are only seen in the dark when they break cover of the coral rubble for a moment to mate in open water.
A Spanish dancer is a large nudibranch A Spanish dancer is a large nudibranch
The problem with getting a glimpse of these last two night stars of the tropical marine environment is that any white light will scare them back into hiding. Nowadays, some dive lights and video lights come with alternative red beams that the fish don’t appear to see. A typical  example comes in the form of the i-Torch Pro6+ although there are many others to choose from.
Mandarin fish photographed with the aid of a red aiming light. Mandarin fish photographed with the aid of a red aiming light.
Of course, if you video any subject by the light of a red lamp it will record as red but if you are making still photographs you can line up a subject under a red aiming light and then capture their image with a pulse of white light from an underwater flashgun or strobe.
Caribbean spiny lobster Caribbean spiny lobster
What's the difference between an underwater video light and a diving light? The diving light will have a narrow beam which is not usually very even. It gives a hotspot of focused light and a peripheral beam that may be composed of concentric rings. It allows us to concentrate on one subject whilst being aware of what else might be going on around us. On the other hand a video light gives a wide and perfectly even beam in a colour-temperature range that is acceptable when viewing the footage later. If you used an ordinary diver’s light for video, the image would be unacceptably patchy. Equally, a video light does not punch its way far into the water and only a has a limited range. You'll see the weird and the wonderful at night. Animals such as this decorator crab, self covered with its adornment of sponges.
Decorator crab Decorator crab disguised with a covering of sponges.
Whether you want a light for diving or for underwater video-making, we hold a large selection at Ocean Leisure and Ocean Leisure Cameras. If it's a video light you need, you'll discover a choice from 1000 lumens output to a massive 6000 lumens. If you want a diving torch, we stock a wide selection of those too.

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