Are the new jelly fish (one instead of three….) intelligent or are they dumb? Here's what I have found:
They do exactly what King have told them to do. So if we are meant to fail a level they'll either remain absent or go for the "wrong" candies, if we are meant to pass the level there will be lots of them and they will go the right candies. They are King's little helpers to make sure the level plays the way it is meant to be played.
They aren't dumb at all. They are playing the algorithm.
I've not got huge amounts of time to gather much evidence to back this up, but I am pretty sure I've seen this play out in the game. I have not yet seen a fish go for the "wrong" candy. They only do so in levels where King have programmed them to stop us from passing the level. This does not make them dumb at all. It makes them a very clever tool to control outcome of the levels!