well...considering that their brains are the size of a single crumb, i doubt many of them are smart, but teh smartest i think i heard somewhere that they are tangs or gobies. Gobies have good "safety strategies", ie they wave their tail to signal to a pistol shrimp that something is amiss. tangs use their long mouths to get safely to teh core of an urchin to kill and eat it and not get hit by the spines. other fish may have certain smarts.