» » Cryptobenthic fishes fuel coral reef ecosystem functioning

Cryptobenthic fishes fuel coral reef ecosystem functioning

Cryptobenthic fishes fuel coral reef ecosystem functioning
On reefs around the world, fishes display a remarkable abundance and diversity of shapes and colours. However, perhaps even more remarkable is that most casual observers on reefs probably do not see half of the fishes that live there. This «hidden half» of the fish community is comprised of cryptobenthic reef fishes – adult fishes typically less than 5 cm long that are visually or behaviourally cryptic, and live near to or even within the seabed. The formal name for these neglected animals is «cryptobenthic reef fishes»: «Crypto» because they blend into their environment, either visually or by their behavior, and «benthic» because they live near, or even within, the seabed.


Cryptobenthic reef fish communities can be comprised of many species and families, but perhaps the most common and widespread members are the gobies (family Gobiidae) and the blenny-like fishes (suborder Blennioidei). While small camouflaged fishes may not sound particularly exciting at first, cryptobenthic reef fishes display extraordinary diversity and are of critical ecological importance on reefs worldwide.


Cryptobenthic reef fishes live fast and die young. For most of them, growth, reproduction and death happen at extraordinary rates. After settlement on the reef, often in a very specific microhabitat, adult fishes spend most of their time feasting on microscopic prey, such as small invertebrates (e.g. copepods), filamentous algae, coral mucus or detritus. Most of the energy gained from feeding is used for growth, which lets cryptobenthic reef fishes grow rapidly throughout their lives. The remaining time and energy is spent largely on a surprising variety of different social and reproductive strategies, including sex changes, territoriality, and both monogamous and polygamous reproduction. Some species, like the dwarf goby Eviota sigillata, can produce 7.4 generations per year, which results in a steady stream of new recruits of cryptobenthic fishes to the reef. After a few weeks, it’s all over. In fact, with a maximum age of just 59 days in the wild, E. sigillata currently holds the record for the shortest lifespan of all vertebrates, and the goby Coryphopterus kuna is the only known fish that has a larval stage that lasts longer than its adult lifespan.


Most larger fish broadcast their eggs into the sea and let currents spread them far and wide – a hedging strategy that ensures there will always be a few larvae floating around to replenish a population if a disaster strikes. Cryptobenthic reef fish have the opposite strategy: They produce fewer offspring, keep them close to home, and invest heavily in them by providing an unusual degree of parental care. Some brood their eggs in a pouch, some in their mouths, some tuck them behind their pectoral fins –that’s called armpit brooding. Two groups give birth to live young – a rarity among coral reef fishes. Even species with more conventional egg-laying approaches, where the female attaches a sticky egg mass to a coral branch, a sponge, or a rock, provide those eggs with postnatal care. It’s mostly males who perform egg-minding duties, which include fanning the eggs to keep them well-oxygenated, and cleaning them to prevent the build up of detritus. Some species may even provide the eggs with antibiotic protection against infection. As a result, the larvae of cryptobenthos fish are much more likely to survive to hatch compared to other fish. And as scientists have found out, two-thirds of all fry on reefs are precisely cryptobenthos. This overwhelming abundance of cryptobenthic larvae fuels reef trophodynamics via rapid growth and extreme mortality, producing almost 60% of consumed reef fish biomass.


Up to 70 percent of cryptobenthics die each week mostly in the jaws of bigger animals. They are eaten by virtually any reef predator – fish, mantis shrimps, crabs, even some predatory mollusks. The diet of juvenile groupers has been found to consist of almost 88,6 percent cryptobenthic fish.
Although cryptobenthics are often overlooked, their distinctive demographic dynamics may make them a cornerstone of ecosystem functioning on modern coral reefs.


While diving in Bali, you will be able to observe a variety of cryptobenthic reef fish at various dive sites. Be sure to take a closer look at these cute babes.


(Based on materials from scientific journals Current Biology (June 05, 2017) и Science (21 Jun, 2019))



Toothy goby or Mozambique ghost goby (Pleurosicya mossambica). Tulamben, BaliToothy goby or Mozambique ghost goby (Pleurosicya mossambica). Tulamben, BaliToothy goby or Mozambique ghost goby (Pleurosicya mossambica). Tulamben, BaliToothy goby or Mozambique ghost goby (Pleurosicya mossambica). Tulamben, BaliToothy goby or Mozambique ghost goby (Pleurosicya mossambica). Tulamben, BaliToothy goby or Mozambique ghost goby (Pleurosicya mossambica). Tulamben, Bali
Wide-Barred Shrimpgody (Amblyeleotris latifasciata). Tulamben, BaliWide-Barred Shrimpgody (Amblyeleotris latifasciata). Tulamben, BaliBroad-banded shrimpgoby (Amblyeleotris periophthalma). Tulamben, BaliBroad-banded shrimpgoby (Amblyeleotris periophthalma). Tulamben, BaliFlagtail Shrimpgoby (Amblyeleotris yanoi). Tulamben, BaliFlagtail Shrimpgoby (Amblyeleotris yanoi). Tulamben, Bali
Spotted prawn goby (Amblyeleotris guttata). Menjangan, BaliSpotted prawn goby (Amblyeleotris guttata). Menjangan, BaliSpotted prawn goby (Amblyeleotris guttata). Menjangan, BaliSpotted prawn goby (Amblyeleotris guttata). Menjangan, BaliSpotted prawn goby (Amblyeleotris guttata). Menjangan, BaliSpotted prawn goby (Amblyeleotris guttata). Menjangan, Bali
Blueband Goby or Golden-head Sleeper Goby (Valenciennea strigata). Tulamben, BaliBlueband Goby or Golden-head Sleeper Goby (Valenciennea strigata). Tulamben, BaliOrange-spotted Sleeper Goby or Maiden Goby (Valenciennea puellaris). Tulamben, BaliOrange-spotted Sleeper Goby or Maiden Goby (Valenciennea puellaris). Tulamben, BaliDecorated Goby (Istigobius decoratus). Tulamben, BaliDecorated Goby (Istigobius decoratus). Tulamben, Bali
Filament-finned prawn-goby or Black-ray goby (Stonogobiops nematodes). Tulamben, BaliFilament-finned prawn-goby or Black-ray goby (Stonogobiops nematodes). Tulamben, BaliFire goby (Nemateleotris magnifica). Amed, BaliFire goby (Nemateleotris magnifica). Amed, BaliBroad-banded shrimpgoby (Amblyeleotris periophthalma). Tulamben, BaliBroad-banded shrimpgoby (Amblyeleotris periophthalma). Tulamben, Bali