One of the interesting symbiotic relationship that can be observed in a home reef aquarium is the tiger pistol shrimp and its symbiosis with a watchman goby.
In this relationship the shrimp does a lot of the heavy lifting — literally, as it has to dig the burrow where they live with its companion goby. The goby in return acts as the eyes of the shrimp who otherwise has very bad eyesight. The shrimp usually feels comfortable only when it can touch its goby with its antennae.
The shrimp is very well equipped for digging, its claws function as shovels, and it can relentlessly dig all day like a small underwater bulldozer.
The larger of the shovel-like claws also acts as a ‘pistol’. The shrimp can expel an air bubble from it with a speed over 100km/h and stun prey with it. When the shrimp does that, it does make a loud clicking sound clearly audible outside the reef tank — or even in another room.
Both the shrimp and the goby tend to be very timid, I had a hard time taking pictures of them.
Tiger pistol shrimps are relatively harmless in a home reef aquarium. Some other species or pistol shrimp, in particular the stunningly beautiful non-symbiotic species, the Michael’s pistol shrimp, can become quite a pest since it loves to eat other shrimp without any regard how expensive that other shrimp was.
Yellow prawn-goby on Wikipedia.
Deadly pistol shrimp that stuns prey with sound as loud as Concorde found in UK waters Daily Mail Online.
A Shrimp Is One Of The Loudest Animals On The Planet.
Tiger Pistol Shrimp (Alpheus bellulus).