The Census of Marine Life project has uncovered an interesting goby fish in Guam that forms a symbiosis with a snapping shrimp. The shrimp excavates a burrow, and the fish guards the borrow and uses it as a dwelling. The level of coordination between the two is unclear, but would definitely be of interest in terms of understanding macro-symbiosis.
My all time favorite amongst these fishes is the awful venomous Rhinopias eschmeyeri. Not far behind is the drab, but deadly Uranoscopus bicinctus. The scorpion fish family is Scorpaenidae which has many subdivisions:
1) Scorpaeninae: Scorpionfishes and Lionfishes. 2) Synanceinae: Stonefishes 3) Choridactylinae: Stingfishes and Devilfishes and 4) The Leaf fish (Taenianotus). They are characterized by their odd shapes and spines with venom on their backs and fins.
Lionfishes have been observed to show cooperative hunting behavior, something worth investigating further.