Ho Yay Shipping: Hubie and Rocko. Plenty of viewers can attest to seeing it. Particularly during their Friend Song.
There's scenes where it's Played for Laughs, such as Rocko waking up with his arms around Hubie, and not realizing it until Hubie's already wide awake, or times when you swear it was done on purpose, like later in that same scene where Hubie says, "It's beautiful!" and Rocko (who is looking down at Hubie or a moment) stutters and says yes, too, before seeing that Hubie was talking about an iceberg.
Moral Event Horizon: Drake makes no attempts to hide the fact he'll beat Marina if she doesn't do as he says. He also outright threatens her with death if she refuses to mate with him during Don't Make Me Laugh, saying she'll "be a shark's dinner" and that he'll write her epitaph if she refuses. This is flat out rape through threats to her well-being. Similar to Gaston, Drake at first seemed like just a Jerk Jock but then shows he's much more evil than that.
Narm: Thanks to Hubie's voice and odd design, it's pretty difficult to take anything he does seriously.
Nightmare Fuel: The Orcas. In many a family film, killer whales have been shown to be lovable pals. In this film, they're shown to be as predatory as they are in real life.
Ugly Cute: Though as the poster shows, some of the characters fail at the cute part. To be fair, in the movie Drake's the only really ugly one. Hubie and Rocko just happen to be caught in rather unflattering poses.