A study led by Alexander Vail, a Gates Cambridge Scholar at the University of Cambridge's Department of Zoology, found that groupers and coral trout perform a pointing signal to indicate the location of hidden prey to cooperative hunting partners including moray eels, octopuses and Napoleon wrasses.They go on to say:
The grouper's signalling shows what are considered key hallmarks of being carried out with intent - that is, the fish has a goal in mind and uses communication to try and achieve it - rather than being an inflexible gesture. Key evidence is that the grouper elaborates on its headstand signal when the moray eel does not react appropriately to its signal and swims over to the eel, tries a different signal and in some cases even tries to push the moray in the prey's direction. The researchers also observed groupers waiting above a hidden prey for up to 25 minutes before signalling to a passing predatory partner. They say this suggests groupers may perform at an ape-like level in a memory task commonly used to assess cognitive ability.Read more at the University of Cambridge's website. The research has been published in Nature Communications.
I'll add this to Tool-like behavior in the sixbar wrasse, Thalassoma hardwicke, which detailed the use of rock anvils to smash food into manageable pieces (a behaviour I see regularly in my moon wrasse, Thalassoma lunare). Another nice example I use is my old archerfish, Toxotes jaculatrix, who realised that if it shot a drop of water at me sitting at my computer I would likely feed it.
Don't underestimate our piscine pals.