Odd Couple: Shrimp goby and blind shrimp

Spotted Shrimp goby – Amblyeleotris guttata, Shot in Dauin, Philippines.

These shrimp goby live in a symbiotic relationship with shrimps(they sharing same burrow). The shrimps are almost blind and need the goby to keep an eye out for predators. Shrimp goby needs a hiding place and benefits from living in the burrow excavated by the shrimp.

Goby in this video: Spotted shrimp goby (Amblyeleotris guttata).

3 minute long original footage compressed(fast forward) in 35sec.
Filmed at Ambon, Indonesia / Canon 7D, 100mm

Snapping (Blind) shrimp – Alpheus sp., Shot in Dauin, Philippines.

I’m sure many people already know about relationship this shrimp and goby.
But I’m still very curious to know how they actually decide to pair up in the first place?