Please visit our Sponsors

Related FAQs: Red Sea Biotopes

Related Articles: Reef Slope, Sandy Slope, Biotopes, Fishwatcher's Guide to the Red Sea, Triggerfishes of the Red Sea, Butterflyfishes of the Red Sea, Angelfishes of the Red Sea,  

Marine Aquarium Biotopes: Pt.1

 Red Sea Reef Flats/Plateaus 1 of 2

Bob Fenner

Typical Red Sea Reef Flat Scene

    Biotopic presentations aka "specialty tanks" entail the blending of habitat, physical and chemical modeling to match life found in a given environmental niche. Many arguments have been advanced encouraging aquarium hobbyists to set-up their captive displays along the lines of these environmental and biological niches. Indeed, settings that seek to mimic a given part of the world's seas in their physical and living make-up have many advantages. 

    Being more natural, biotopic presentations provide conditions that are complementary to the life forms utilized; that in turn correlate better with each other that the typical hodge-podge collection of most set-ups. The approach of just buying, mixing what is pretty and available is ill-advised in many cases. Not appreciated by many aquarists are the many ways and means of negative chemical and physical interactions that exist amongst aquatic species. Leather Soft Coral (alcyoniid) terpenoid production; overgrowing/shading and digestive dominance, Sweeper Tentacle et al. stinging amongst cnidarian species are but a beginning of a list of the several kinds of mechanisms marine life uses to compete for habitat and food resources. 

    You might think, "All will be fine if I secure livestock from one area and type of environment". But simply selecting and arranging your livestock from a given geography, environmental type and trying to provide similar conditions found there will not eliminate such "aggressive behavior". Sea life in all localities in the wild interacts amongst itself in myriad deleterious ways as well. Prudence in placement, order of introduction and maintenance must still be employed by you to minimize to acceptable degrees such influences. 

    On the positive side, biotopic presentations are superior in matching the physical needs of mixed livestock. Obviously, organisms that hail from a particular area and environmental niche share lighting, water movement and other habitat considerations. 

    A further benefit of biotope approaches is that they provide foods in the way of DOC's (Dissolved Organic Carbon), meiofauna and macrophytes that and more that again coordinates as nutritive webbing in ways, degrees more beneficial than a random mixing of livestock. A ready example of this phenomenon may be the keeping of nudibranchs. Most of these Naked-Gill Snails have such specialized, restricted diets it is only prudent to collect them with such living foodstuff and culture them together. Clearly, biotopic designs are the best means of such co-husbandry.

    Lastly, a note re the "human" potential of attempting biotopic set-ups. Much is to be gained by encouraging these adventures in aquarium keeping. Knowledge and pleasure of discovering how environmental niches and their biota "work" to put it generally. 

About the Red Sea:  Make-Up, Features of Aquarium Importance

    Along with the principal Hawaiian Islands and Mexico's Sea of Cortez the Red Sea is an area of high endemism, with some one quarter of species of shallow water marines only found in the locality. What's more, for aquarists, the Red Sea's inhabitants are stunningly more gorgeous and notably easier-going, in comparison with the same species whose ranges extend into the Indian, Pacific and other oceans. 

    And what a resource! The Red Sea is about 2,000 kilometers (1,250 miles) long, and more than 2,000 meters deep in places, with intact coral reefs along almost its entire coast. As time has gone by, development of infrastructure in some countries adjoining it, normalization of international relations and desire for hard currency exchange has driven the evolution of marine livestock collection and improvement in cost, quality of product from the region. 

    Of pertinence to marine aquarists is the Red Sea's general physical make-up. Due to it's narrow inlet to the Indian Ocean to the south (and a bit from the Mediterranean Sea via the Suez Canal to the north), the water here is more salty, registering a specific gravity of about ten percent more (1.0275) than the "standard" found in most of the worlds seas. 

    Being relatively narrow and long, with constricted in/outflows, and oriented north/south, the Red Sea has restricted tides (typically 0.5 to a meter) and though flow rates can be exaggerated locally, circulation is not as brisk as many other seas, regions. This being stated, especially for reef flats/plateaus water movement in a typical aquarium (with a handful of turns per hour) is certainly more dynamic than the vast majority of captive conditions. 

    Light intensity is high here, particularly in shallow waters of course. On calm days with the sun directly overhead it is brighter than almost any artificially illuminated aquarium I have encountered, and there are few days that it isn't very bright at mid-day. More light rather than less is the general rule with Red Sea aquariums. 

Reef Flats of the Red Sea:

    As stated above these are nearly continuous along the coast of the Red Sea, varying in width from a few to several meters in width, with occasional expansions along peninsular leading edges, the few islands and submerged reefs. Depth varies little, most tides adding, subtracting only a foot or so any given day. The reef flat or plateau is rarely completely exposed in the Red Sea.

Images of the nearshore reef flat above and below water near Sharm el Sheik, Gulf of Aqaba. At left Johnston Reef, middle is a view from toward the shore. The brown area is the reef flat/plateau, the blue the sudden drop-off typical of the reef slope lip. At middle: The dark area to shore is the reef, with a darker drop off (reef slope) and sandy bottom and patch reef seaward. At right: abundant stony corals of the families Acroporidae and Pocilloporidae dominate, with a Klunzinger's and female Bird Nose Wrasses, and "King" of the reef Sohal Tang in view. Photos: Mike Kaechele at left, Leng Sy middle and right.

Video of Red Sea Reef Flat:  to be done: place link to video at right, instructions to right click icons.  

Biota of the Reef Flats of the Red Sea:

    Here we will list and describe the species of most use and availability to aquarists. Of course there are many more species than can be practically detailed here and some species that should not be offered to the hobby do make their way into markets. As a precautionary measure we'll include a table of ones that are often for sale, but shouldn't be due to historically dismal survival records. 

Rest assured, your eyes do not deceive you. The life here is really this colorful and beautifully marked. 

Most Common Species of the Red Sea Reef Flat

Misc. encrusting Red Algae, filamentous Greens. Here's a colony of the Coralline, Peyssonnelia sp. 
Stony Corals; almost entirely Pocilloporids (Cat's Paw Corals) and Acroporids (Staghorn Corals), of the genera Acropora, Stylophora, Pocillopora. Most commonly encountered forms include Pocillopora verrucosa, Stylophora pistillata, Acropora humilis, A. corymbosa, A. hemprichi... and of course the almost omnipresent Fire Coral, Millepora (see below) 
Fire Coral, Millepora spp. This stinging hydrozoan is literally everywhere underwater in the Red Sea. Smaller, less conspicuous than in deeper environments; encrusting and columnar principally, rather than arborose. 
Sohal Tangs, Acanthurus sohal. If there is a "key species" of fish of the Red Sea Reef Flat, this is it. "The King". One to a tank unless it's huge, and best to place this fish species last... as it can be/come very territorial.
Damselfishes, family Pomacentridae; two in particular, the Sulfur Damsel, Pomacentrus sufureus and the Indo-Pacific Sergeant Major, Abudefduf vaigiensis (shown).
Klunzinger's Wrasse, Thalassoma rueppellii. A very typical inhabitant of the reef slope. 
Red Sea Bird Wrasse, Gomphosus caeruleus. A male shown at right, coverage on the species below with the Red Sea Reef Flat Fishes coverage.
Purple Tang, Zebrasoma xanthurum. A beauty with a penchant for hanging out at the reef lip, beginning of the rocky reef slope, making periodic foraging forays up on top. 
Butterflyfishes; Chaetodon semilarvatus, C. paucifasciatus, C. auriga, C. fasciatus and Heniochus intermedius "visit" the reef flat for short feeding forays (or to avoid divers), but are more often encountered "down the reef slope" over the edge, dipping in and out of overhangs and rocky caves. These will be covered in the next installment, pt. 2, the Red Sea Reef Slope. Pairs of C. semilarvatus, H. intermedius shown. 

Species Offered Occasionally from Red Sea Reef Flats that Should be Avoided  

Here's my "warning list" of too historically touchy, inappropriate species that are offered to hobbyists hailing from this region and biotope.

Bicolor Parrotfish, Cetoscarus bicolor. Likely the most commonly sold species of Parrotfish in the aquarium interest... almost exclusively as juveniles. Indo-Pacific, Red Sea to Tuamotus. To three feet in length (not a misprint). Pictured: aquarium juvenile, female and male in the Red Sea below

The Clown Coris, C. aygula. As rambunctious (to put it mildly) as other members of the genus, but an ultimate giant of more than three feet (120 cm. according to fishbase.org) length. Below: a three inch juvenile, a six inch female and two foot male in the Red Sea.

Survey of Best, Available Species of Red Sea Reef Flats:

About Live Rock: Chances are very good that your live rock, cultured or not, will not come from the Red Sea. For purists, base rock can be inoculated and over time, overgrown by organisms recruited from other hard materials, but South Seas originating materials are fine.

Algae: On the Reef Flat are mainly of the Encrusting Reds called Corallines, with some transient (chewed or scrubbed away) filamentous Greens.

Encrusting Coralline Red Algae of several species.  Red Sea image.

Stinging-Celled Life, Phylum Cnidaria: Due to the vagaries of variable wave action, insolation (light and heat from the sun), and other factors, the upper reef flat is a place of harsh and dynamic circumstances. As you can appreciate species diversity and abundance are more limited here than just "over the edge" of the reef lip and slope. Nevertheless there are robust species that dominate this zone. Mainly the Stony Corals, Order Scleractinia, of the following families.

Family Acroporidae: There are three genera of Staghorn Corals in the Red Sea; Acropora, Montipora and Astreopora. The first two are the predominant life forms on the reef flat and may continue to be so "over the edge".

Genus Acropora: Some seven to fifteen species are described from the Red Sea, depending on which reference one follows. A. lamarcki (formerly corymbosa), A. hemprichi, A. humilis are regularly occurring, abundant species. A. haimei can be found in very shallow water, dominating at times.

Acropora lamarcki (formerly corymbosa), Veron 2000. Colonies as corymbose plates up to 2 m across. Plates of short, upright branchlets that are more tapering upward. Axial corallites are exsert, tubular, with inclined, flaring outer lips. Red Sea images. 

Acropora hemprichii (Ehrenberg 1834). Irregularly branched with radial corallites as open thickets, large, round, upright, conical. Axial corallites common, prostate, of thick smooth walls. Most are brown to pink in color, some blue. Red Sea images.

Acropora humilis (Dana 1846). Finger like colonies whose branches are thick, tapering to a dome. Larger branches intermingled with smaller. Radial corallites of two sizes; larger ones in rows slightly enlarged toward base. Below: Red Sea images of a reef flat group of colonies, branch tips and closer. 
Acropora haimei (Milne Edwards and Haime 1860). Colonies of short, upright, tapering branches, with axial corallites which are exsert, tubular and upwardly projecting. Radial corallites similar with sharp-edged lips. Red Sea image.

Over to: Part 2 Red Sea Reef Flat Biotopes

Or on to/down to the next level: The Red Sea Reef Slope 

Become a Sponsor Features:
Daily FAQs FW Daily FAQs SW Pix of the Day FW Pix of the Day New On WWM
Helpful Links Hobbyist Forum Calendars Admin Index Cover Images
Featured Sponsors: