If you look carefully, you can see a pair of gobies in the centre of the photo.
On our trip to Pulau Semakau, we spotted some gobies! The spotted (no pun intended) gobies found on Pulau Semakau somewhat resemble pictures of saddled shrimp-gobies (Cryptocentrus maudae) or a slender-lined shrimp goby (Cryptocentrus leptocephalus), and belong to Phylum Chordata, which includes humans and other vertebrates (in fact, fishes are classified under Subphylum Vertebrata!)
Gobies are fishes which vary largely in size (again, no pun intended), with some tiny examples that we saw at around 1.5 cm long, while other species of gobies can grow up to 8 cm or longer. Gobies are often speckled, blotched or spotted, with colours that vary depending on their environments. For instance, the gobies on Pulau Semakau were generally a dull brown in colour, which would have made them harder to spot had they not been darting around our ankles as we waded through the water, while gobies inhabiting tropical seas apparently taking on brighter colours, reminiscent of the vast multitude of colours of corals and sponges in tropical seas. Certain species of gobies can also change colour in a matter of minutes, allowing it to blend in perfectly with its surroundings.
While the goby fish may be small, do not be fooled by its size – it is a carnivore, that feeds on small insects, their eggs and larvae, and plankton. In fact, because goby fish are small and slim, this enables them to dart around quickly in the water, allowing them to catch fast moving prey, and escape predators while hunting – much like how we take-away at a fast-food restaurant.
The gobies we saw on Pulau Semakau seemed perfectly at home with their surroundings – even when predators are about. The predators of the goby fish include birds, and this could prove to be a problem especially when they are trapped in small puddles of water during low tide. Fortunately, the aforementioned characteristics of the goby allows them to thrive in such an environment. As previously mentioned, the patterns and dull colour of the goby fish allow them to blend in with their surroundings, which are often lined with mud and sand. This aids them in escaping predation. Being small and slim once again proves to be an advantage, as they are able to quickly and easily slip into crevices, holes or burrows – during low tide, this proves to be especially beneficial as they can escape predation when they are trapped in puddles, and avoid dehydration from the scorching sun by taking shade in burrows!
However, the most fascinating adaptation we noted about the goby fish was the mutualistic symbiosis these small fishes share with pistol shrimp, the cowboys of the sea. Goby fish have evolved to have good eyesight – they use their vision to keep a lookout for predators, but find it difficult to dig out a burrow in the sand for themselves, so they rely on naturally formed holes or old burrows as a means for escape. The pistol shrimp, on the other hand, is talented at digging burrows, but have poor vision. The strengths and weaknesses of these two animals complement each other – and so, certain species of pistol shrimp and gobies have found themselves roommates. While the pistol shrimp digs the burrow and keeps the entrance free of debris, it keeps tactile communication with the goby by keeping an antenna in contact with it. Meanwhile, the goby acts as a sentry outside the burrow, looking out for predators that may approach the pair. When the goby sights a predator, it darts into the burrow, and the shrimp will follow suit. Although we didn’t manage to see (pun intended) this in action, most burrows are large enough to accommodate a pair of goby-shrimp pairs, meaning that the burrow is large enough to accommodate four!
References:
https://www.sciencedaily.com/releases/2014/10/141015143149.htm
https://www.nparks.gov.sg/mygreenspace/issue-13-vol-2-2012/conservation/swimming-into-the-record
The Biodiversity Press 
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