Two fishes this week: Plectropomus pessuliferus (roving Coral Grouper) and Gymnothorax javanicus (giant Moray Eel). This PLoS article (no subscription required) describes research that demonstrated these two species actually co-operate when hunting. The groupers are very effective open-water predators, while moray eels are very good at getting into reef crevices. Prey species can escape one or the other hunter, but with both on the scene, there's nowhere to run to.
Here's the summary of the article, emphasizing the role of intelligence among fishes. The article includes four very nice videos, which are quite large and take a long time to download and buffer.