Wabu is an energetic Paca with a lot of things to say! Their tail swishes quite a lot, though the water never seems to drip. The fish swim happily around inside. They feed the fish that live in their tail, though whether they actually need to do that or not varies in opinion from Paca to Paca. They're bold and take (way too many) risks, never really worrying about the outcome.
They love fish, and have a fish tank full of them! Whenever they need to transport them, they just load them up in their tail with the rest of the fish and move them around. They get scolded for this, after the last time when they forgot to take the fish out, and now there is a foreign fish living in their tail with the rest of the natural fish. They don't remember which one is the foreign fish, so they cant remove it without fear of accidentally removing one of the naturally occurring fish in the tail. (It's actually quite obvious which one is the foreign fish, as it's the only one with a pattern, but Wabu refuses to acknowledge it)
Wabu is Robu's good friend! They help get Robu out of their comfort zone and try new things! They also get Robu into a lot of trouble by proxy. Whoops.