top of page

206. A curious Stripedfin Grouper (Epinephelus posteli)


A curious Stripedfin Grouper (Epinephelus posteli) approaches the camera in the shallow turbid waters of KwaZulu Natal in South Africa.

The beautiful, healthy, and pristine but relatively shallow reefs of Manzengwenya in the northern part of KwaZulu Natal, near the Mozambican border, are teeming with marine wildlife. Big schools of snappers, fusiliers and breams, sharks, moray eels, and big groupers patrol these subtropical and pristine reefs.

The Stripedfin Grouper, sometimes locally called “Tiger Fin Rockcod”, which is endemic to the southwestern Indian Ocean (from Durban in South Africa to Ihambane in southern Mozambique and a small zone of the southwestern reefs of Madagascar and probably the French island of Réunion), seems to be a relatively rare encounter. The South African reefs where this grouper has been filmed are also rarely visited by scuba divers, which might explain the curious and investigative behaviour of this large grouper.

The Stripedfin Grouper, an active hunter of crustaceans and small to medium-sized fish, is known to grow slightly larger than 1m/3ft and weigh up to 12kg/27lbs or so.


When we dived these lush subtropical African reefs, there was a rather big swell present that made us roll sideways, forwards, and backward. Just like all the fish on this reef, we were at the mercy of the ocean’s movements, which made filming quite a challenge. This area with dense hard coral growth was quite shallow with a maximum depth of approximately 18m/60ft or so. Shallow reefs are more prone to swells, as waves break when going over shallow bottoms. If the site had been deeper, the swell would have been less noticeable, and making an underwater video would have been easier.

Trying to avoid swimming close to the corals so that neither we nor the corals would be hurt or damaged, we hung in the midwater in an attempt to keep our cameras as stable as possible. In my humble experience, I concluded that it was best practice to stay neutrally buoyant in the mid-water and go along with the dramatic water movements and to keep the camera as horizontal as possible. By ignoring the lateral movement of this annoying but not insurmountable swell, I moved at approximately the same rhythm as the fish I was filming and thus kept my subject framed.

In post-production, I stabilised the footage first by using keyframes. This technique already kept the big Stripedfin Grouper as central as possible in the frame. Once this was done, the stabiliser of the editing software smoothed out the small fluctuations of the fish’s position in the picture.

Due to the setup of the scene (wide-angle) and the shallowness of this immense large coral reef, this footage was filmed without any video lights. The built-in orange colour-correcting filter of the submersible protective camera housing did a great job in preserving all the natural colours of the underwater scene.

In post-production, I boosted the contrast slightly and added music that would go as much as possible with the rhythm of the ocean’s pulse.

Filming location:

This short underwater videoclip has been filmed in KwaZulu Natal, South Africa 🇿🇦

Join us on a journey of discovery and entertainment as we explore fascinating marine wildlife topics and explore the many exciting underwater adventures on our YouTube channel and our Facebook page!

Unlock the power of marine wildlife videography and unleash your inner filmmaker with our online Marine Wildlife Videography course!


bottom of page