“You can’t ever bluff the fish” boasted the wily old poker veteran. And that’s true if the “fish” called every bet, but that is a very rare breed of fish. Most “fish” at times fold, and are often prone to giving away information that they are about to. Tells abound with fish.
That said, with “fishy” players, you need to be much more situationally selective. A few fish are fishy because they fold too much, but that’s not typically true. In short, bluffing is doable, but the situations are generally few and far between.
Most fish call with a wide pre-flop range that will often whiff the flop. That creates value for pre-flop isolation plays and flop continuation bets. Of course, some flops are whiffier than others, and players have differing post-flop calling frequencies. The trick to being a successful bluffer in the “fish pond” is to compartmentalize. Put those that almost never fold in one compartment, those that call with overcards in another. Think about who plays ‘fit or fold” and learn which boards they can be moved off of. Are there any who seem like they are playing scared? You can develop your own compartments, simplify or complicate, the variations of opponents is immeasurable.
Rainbow boards that have a high card remove some/all of the overcard range from an opponent. Those with few legitimate straight/flush draws add still greater value to your bluffs. Consider the board texture, what will this particular opponent(s) call with? What percentage of their current range is a calling hand? What size bet will fold those hands? Is the pots size worth the bets risk?
Opportunities to bluff in loose games are fewer, but that doesn’t mean that a limited number of well selected bluffs can’t have positive value. If you select the right situations, not only will your bluffs have positive EV but when your often calling opponents know that you bluff, it will both widen their calling range and create better value betting situations because they are likely to call bigger wagers.
So, don’t just give up on bluffing because the game is loose. Find the right spots and it will add value to your game.