In an attempt to locate a dusky jawfish, Chris encountered plenty of fascinating creatures while diving in the Caribbean. Find out what lives on the reefs around Saint Lucia and become inspired to recreate it in your reef tank.
Creating a biotope aquarium is something that is far more common in the freshwater hobby than it is in the marine one. I recently shared my experience diving in the Red Sea, and the various reef zones and species present in the hope of inspiring more saltwater aquarium keepers to give biotope reefing a go.
To follow that feature, I am excited to share what I saw when I visited the Caribbean, focusing specifically on the species that live on the reefs around Saint Lucia. Read on to discover what I encountered when I went searching for a dusky jawfish (Opistognathus whitehurst). Perhaps after reading this, you'll want to build your own Caribbean reef!
First Impressions Of Saint Lucia's Reefs
When I arrived at Saint Lucia, local fishermen were cleaning their catch along the waterfront. While mahi mahi and horse-eye jacks dominated the day's haul, my attention was fixed on the shallows and the reef life beyond.
The beach was deserted, but there was plenty of evidence of human activity beneath the surface as I swam out from shore. Human debris littered the sandy seabed, but like many muck-diving sites, life had quickly colonised it. Algae enrobed the cans, while tiny gobies darted into a beer bottle for safety, their exact identity hidden behind translucent glass.
Gold-spotted eel - All photos by Chris Sergeant unless otherwise stated
In terms of larger residents, the silt was very much the realm of the eels. Gold-spotted eels (Myrichthys ocellatus) rooted through the sand close to the seagrass, while others utilised the soft sediment to construct underground homes. Margintail congers (Paraconger caudilimbatus) are too large for home aquariums, but under the right conditions, garden eels (Heteroconger longissimus) could make for an unusual Caribbean set-up.
Forming large colonies, each garden eel inhabits an individual burrow, with its top third protruding up into the current, ready to catch passing zooplankton. Deep sand beds and strong currents are a prerequisite for success with these fish, but in a large tank with regular feeds, the results can be striking.
A Man-Made Biotope
Kicking out towards a small jetty, I crossed a line of seagrass where juvenile fish flitted about amongst the leaves, while a typically nocturnal Caribbean reef lobster (Panulirus argus) scuttled about the substrate, pictured below.
The jetty legs themselves supported a huge array of life – a myriad of hydroids, algae and sponges entwined together to form a living, breathing carpet. Perfectly camouflaged seaweed blennies (Parablennius marmoreus) and characterful molly millers (Scartella cristata) danced between the pilings.
Related article: Characterful Blennies For Your Reef Tank.
Compared with the surrounding sunlit waters, the jetty provided a shadowy refuge and the perfect vantage point for ambush predators. An invasive lionfish (Pterois sp.) sat silhouetted against the surrounding blue. While sadly technically biotope-correct, they are best avoided within a ‘true’ Caribbean reef assemblage.
Punctuating the algal mats were feather duster worms (Sabellastarte sp.). Holed up in parchment-based tubes with just their feathery radioles exposed, they filter food from the passing current before retracting back at the first sign of a threat. A less welcome sight for aquarists, however, were the numerous Caribbean bearded fireworms (Hermodice carunculata) that roamed almost every surface, pictured below.
Related article: Marine Hitchhikers: Natural pest control for reef tanks.
Life On The Caribbean Reef
Next to the jetty, the sheer cliffs rose above the sea. Below the waves, the base of the cliffs formed the starting point of the reef that fringes the bay.
Here too, the dappled sunlight dissolved into shadow, but despite this, the rock face was awash with colour. Sun corals (Tubastraea coccinea) lined every overhang, their vivid feeding tentacles waving in the flow, pictured below. These non-reef-building, large polyp stony corals are non-photosynthetic, thriving in areas that sunlight cannot penetrate and gaining sustenance from their catch.
Equally eye-catching were the golden zoanthids (Parazoanthus swiftii) that grew symbiotically on various sponges – typically the green finger sponge (Iotrochota birotulata) or the brown tube sponge (Agelas conifera). Their vibrant colours highlight their toxic nature, warding off sponge-eating predators like the rock beauty (Holacanthus tricolor), while the zoanthids feed on the larger food particles that the filter-feeding sponge rejects – a win-win arrangement.
A chain moray (Echidna catenata) concealed its body within the rocky labyrinth below the sponges with just its head exposed. These blunt-toothed morays might prefer the taste of crustaceans, but that doesn’t mean they won’t opportunistically take the odd fish, so great care should be taken if considering housing one within a community Caribbean reef.
At this point, I headed into deeper water, and coral colonies started to replace the carpets of Penicillus that dominated the shaded shallows. Unlike previous excursions in the Red Sea, where colonies of multi-coloured Acropora, Millepora and Pocillopora sat interlocked, vying for space, the corals here were spread out as if they were adhering to a territorial agreement prohibiting any encroachment.
Initially, small outcrops of stony corals dominated the reefscape. Little, domed Siderastrea straddled bare patches of rockwork, while rose coral (Manicina areolata) and Caribbean sea mat (Palythoa caribaeorum) were dotted about in between.
Encouragingly, mountainous star coral (Orbicella faveolata) was another of the more commonly encountered species, despite its IUCN Endangered status, pictured above. It was a perfect vantage spot for scores of neon gobies (Elacatinus oceanops).
Related article: Colourful gobies for your nano reef.
Deeper Reef Inhabitants
Pushing deeper, the corals might not have been quite so vivid, but their intricate stony structures were no less eye-catching. I encountered a pair of longspined porcupinefish (Diodon holocanthus) swimming lazily over patches of finger coral (Porites porites) – distinguishable by their irregular-shaped branches growing in tight clusters. Maze corals (Meandrina meandrites) were also present here.
When it came to colour, it was the sponges that provided the main contrast. Past 5m (16.5’) deep, huge yellow tube sponges (Aplysina fistularis) appeared, their chimney-like pipes reaching nearly a metre in height in places, while scattered pore rope sponges (Amphimedon compressa) snaked their way between them.
The most impressive Porifera structures were undoubtedly the giant barrel sponges (Xestospongia muta). Rising high above the rest of the reefscape, they provided safety for the fish. Huge shoals of iridescent blue chromis (Azurina cyanea) darted about the structure, along with dusky damselfish (Stegastes adustus), sergeant majors (Abudefduf saxatilis), Spanish hogfish (Bodianus rufus), and initial phase bluehead wrasse (Thalassoma bifasciatum).
Related article: Are damselfish suitable for a community reef?
I came across Atlantic peacock flounders (Bothus lunatus), spotted morays (Gymnothorax moringa), and juvenile French angelfish (Pomacanthus paru) when I passed over the barrel sponges, pictured below. One sponge even played host to a juvenile spotted drum (Equetus punctatus), which appear occasionally in the hobby. While generally considered reef-safe, they have huge appetites and grow fast, so are only suitable for experienced aquarists with large, mature systems.
Not all of the localised corals were dwarfed by their sponge counterparts. At depths of around 10m (32’), comparatively vast colonies of boulder brain coral (Colpophyllia natans) emerged. Like the aforementioned O. faveolata, these grooves housed various nano gobies.
These corals also supported brightly-coloured Christmas tree worms (Spirobranchus giganteus), forming a miniature firework display of reds, oranges, and purples, pictured below. Social feather dusters (Bispira brunnea) also frequented the edges, with these gregarious polychaetes shunning the solo lifestyle for one with friends.
Fans Of The Sea
Gorgonians also lent some height to the local reefscape, reaching up from the substrate and swaying violently in the current. They were home to a variety of reef-dwellers, including the predatory flamingo tongue snails (Cyphoma gibbosum), pictured below.
A stoplight parrotfish (Sparisoma viride) sought sanctuary amongst one particular sea plume in an unusual head-up posture, potentially engaging in a form of pseudo-cleaning.
There were plenty of local reef inhabitants that engaged in true cleaning behaviour. The neon gobies and cleaner gobies (Elacatinus genie) took up residence on large brain corals, waiting for clients, while juvenile French angelfish were also plucking parasites from larger fish.
Still No Jawfish
Conscious that my excursion was yet to yield a jawfish, I decided to take my search down to 25m (82’). The seascape was still heavily dominated by sponges and sea fans, but large outcrops of elkhorn coral (Acropora palmata) also began to break through. Golden crinoids (Davidaster rubiginosus) took up residency around the bases, whilst giant basket stars (Astrophyton muricatum) entwined themselves amongst the branches of the gorgonians, pictured below.
Admiring one vividly coloured crinoid, I inadvertently stumbled upon a long-snouted seahorse (Hippocampus reidi). There’s no doubt that a dedicated seahorse set-up complete with gorgonian backdrop would make a stunning alternative Caribbean reef, as long as any prospective aquarist could keep up with the necessary feeds required by these stomach-less fish.
Gently finning on, I passed numerous azure vase sponges (Callyspongia plicifera) with their intricate, deep-blue latticing hosting various reef inverts, including some familiar yellowline arrow crabs (Stenorhynchus seticornis) waving their pincers wildly in protest at our presence. At the base of these fluorescent sponges were fleshy disc corals (Scolymia lacera), pictured below, relatives of the Australian species commonly available in the aquarium trade.
In terms of other piscine representatives, larger fish species moved through these waters, including barracuda (Sphyraena barracuda), while scrawled filefish (Aluterus scriptus) and queen parrotfish (Scarus vetula) roamed the reefscape.
Closer to the cliff face, a carefully curated collection of broken shells and smashed crab carapaces belied the presence of a good-sized Brazilian octopus (Octopus insularis) lurking in an undercut cave.
Alternative Anemone Inhabitants
As I made my way up the slope to the beach to finish the dive, I passed over a giant anemone (Condylactis gigantea), its elongated tentacles swaying gently. At first glance, it appeared unoccupied. Clownfish, the stereotypical anemone symbionts, aren’t native to the Caribbean, but after adjusting the mask, an array of life came into view.
A bizarrely named slippery dick (Halichoeres bivittatus) darted out, disturbed by the bubbles, while a banded coral shrimp (Stenopus hispidus) scuttled over its side and a pair of unidentifiable tiny yellow gobies, barely the size of a fingernail, skipped over the rock the anemone was adhered to.
Smaller still were another marine aquarium staple, the sexy shrimp (Thor amboiensis), sashaying about, safe in the anemone’s stinging embrace. Closer inspection of the photos taken later revealed another popular reef crustacean, the Pederson’s shrimp (Ancylomenes pedersoni), their translucent bodies and diminutive stature made them almost impossible to spot, pictured below.
Finally… A Jawfish
Then, just to the side, I spotted a face peering from its subterranean den. A little dusky jawfish, situated away from the main reefscape, perfectly camouflaged with the surrounding substrate, pictured below. Every time I approached, it would disappear into the gloom, reappearing only when I had retreated a little.
With my air running low, I quickly made a note of the localised area. Rather than fine sediment, this individual had made its home amongst large, smooth pieces of algae-coated rubble, with not a hint of sand in sight.
As I swam over the substrate, it became apparent it wasn’t alone either, with multiple individuals sitting at the various burrow entrances punctuating the seafloor. With the current picking up here, it was easy to see how any bite-sized critters that got swept up were likely to end up on the menu.
Dusky jawfish are also noted for their tolerance towards conspecifics, and while that may be the case, the burrows along this stretch were metres apart and all seemingly obscured visually from their neighbours, including some similar-looking banded jawfish (Opistognathus macrognathus). Very much a case of out of sight, out of mind in this jawfish community.
With the sun setting, I left these little fish and resurfaced in the shallows. It may have taken the best part of two weeks, but nothing beats encountering an aquarium favourite in the wild. So, as I took off, with one final glance back at the palm-fringed beaches and brilliant blue seas, I plugged the camera into my laptop and pulled out a notepad. I had a Caribbean reef to plan.