Being an unclothed jellyfish, where exactly does Lispel keep all the money he gets for his services? For that matter, where did he keep the bottle of termites he was supposed to use to sabotage the Sea Wolf?
Why does the Sphinx in the Land of Pyramids have a human face, despite being in a world populated almost exclusively by anthropomorphic animals?
In "The White Queen", Dolf taunts Alfred at the end that he can't prove that he tried to steal the Queen's crown, since they're just in one of Alfred's dreams, which he figured out the moment Alfred stepped into the bar that Dolf and his friends were hanging out in. If it's just a dream, and Dolf knew this, why would he try to steal an imaginary crown that wouldn't be worth anything?
Krabnagel disappears from the series entirely after episode 13, when he is arrested after shooting at several police officers. Given the strict laws in Great Waterland at the time, it's quite possible he was sentenced to death shortly after.
In Alfred's world, herring and other fish are still caught and eaten by other animals despite being sentient. Imagine the horror fishermen go through on a daily basis as the loads of herring that they catch scream and beg for mercy...
K. Rokodil is married to a hen. They seem very happy, but if she ever displeased him, he could probably dispatch her with one bite.