136 



COASTAL FISH 











TTze actinia fish Ampiprion, 

 one of the brilliantly coloured 

 inhabitants of the coral reef, 

 has taken up residence among 

 the stinging tentacles of a 

 giant sea-anemone. 



independently like a chameleon. It is an exciting sport catching these 

 pretty and variegated fish. It is often possible to hook them, but the easiest 

 method, perhaps unsportsmanlike but nevertheless extremely efficient, is 

 to poison the water in the pool. 



Of course, numerous other fish occur in this very shallow water, but 

 the best and easiest impression of the enormous variety of fish is conveyed 

 by going out to a coral reef. One day in May 1951 we set out from Singa- 

 pore in our motor launch, chugging between green islands with palm- 

 clad beaches to the coral reef of Pulu Sudong, where we were put ashore 

 in the dinghy. The tide was out, so that we were able to walk about the 

 extensive reef, though hardly dryshod. In the innumerable pools and 

 fissures of the reef there was an immense wealth of animal life: brilliantly 

 coloured fish, including wrasse, parrot-fish, and beautiful little coral fish 

 (Pomacentrus, Abudefduf, Dascyllus, and many others). The most 

 interesting of the Pomacentridse is unquestionably Amphiprion percula. 

 It lies rocking on its side in the stinging tentacles of a giant sea-anemone. 

 To any other animal such an embrace would mean death, but this little 

 creature is unaffected by the dangerous companionship; in fact, it feels 

 so safe there that when we tried to take it it merely went further in. We 

 here have one of the most remarkable examples of symbiosis, a state of 

 association between two animals which benefits both. It is obvious that 

 the fish obtains effective protection in the sea-anemone, and it is prob- 

 able that this sedentary animal gets its share of the food which the fish 

 brings home. Another example, of more doubtful symbiosis, was observed 

 by us on other coral reefs, where a small fish of eel-like form, the fierasfer 

 (Carapus), was seen to crawl backwards into sea-cucumbers. The case 

 is doubtful because it is difficult to see the advantage to the sea-cucumber. 

 We saw a further case of symbiotic association between a small angler-fish 



