A Clan is guided by the principles and beliefs of the cats who came before. The identity of a Clan is carved by those who uphold its values.
At first glance, StreamClan may seem to use their creativity as an aesthetic - using treasures fished out of the river as decorations, or spending time making sure their glossy pelts reflect the fruitfulness of their hunting practices. Perhaps they are much like MeadowClan in their drive to primp themselves up, when given the luxury to.
But to say StreamClan's unique creativity goes to waste couldn't be further from the truth. The river cats are actually quite clever in their ways of hunting and fighting. The water is their home, their protection, their lifeline - no cat in the Vale is able to harness it's potential more than StreamClan. It's what gives them an advantage, and they will always take it.
A river will always keep moving. Sometimes, it overflows. Other time, it's blocked off from its original path. But water will continue to find its way, no matter the obstacle. StreamClan's tenacity is one of their most defining attributes - a whole Clan of stubborn warriors who will never give up without a fight.
They root themselves in tradition, using it as armor against whatever is thrown at them. Much like a river's mark on the stones, StreamClan doesn't forget, and they will never back down. This makes them a hearty opponent, as well as a fiercely loyal Clan.
Unlike the other Clans, StreamClan sports a more noticeable streak of independence.
Perhaps this came about during the Imposter's reign, and the time that came after. StarClan had not given them the help they needed after floods, battles, and infighting. Rest assured, their faith in StarClan still exists, and they follow the code they've laid down. But many warriors look to themselves and each other for guidance, rather than their ancestors.
There has been many occasions when StreamClan warrior had to rely on each other during times of trouble. StarClan had been out of reach - the only guidance they left behind was the warrior code, and StreamClan clung to it tightly.
They want to be good, honorable warriors. If they can't follow the code, then what else do they have? A river full of fish gone to waste for nothing more than rogues. So StreamClan places a lot of importance on the code and what it teaches, hoping it would always be there when StarClan cannot.