He likes to have fun and party. If anything happens he will volunteer to help, he is also very optimistic and friendly ("Bea Stays in the Picture"). And Milo will never let any of his friends leave their friendship ("Fish Sleepover Party", "Dollars and Fish"). He also seems to show that he has attention disabilities ("Fail Fish"). Milo once had to stay in a wheelchair because he rode down a waterfall in a barrel ("Doris Flores Gorgeous"). Milo likes doing various things like sticking his head in a water pipe and swimming down a waterfall ("Doris Flores Gorgeous"). Milo is also very lazy and always wear's Oscar's underwear ("Dances with Wolf Fish"). It is also shown that there is another Milo which looks like him ("The Tale of Sir Oscar Fish"). He can also be very determined for certain things ("Flying Fish"). He describes himself as a guy that "Goes into dangerous adventures for no good reason" ("Peopleing"). His counterpart is Narwhal( ) from Almost Naked Animals
Despite the fact that the two are brothers they're polar opposites of each other causing fights at times. Usually their fights consist of Oscar being upset over something reckless that Milo did, or Milo being upset with Oscar's strictness. The two help each other out though and usually make up at the end of the episode showing that they really care for each other. It is unknown if Milo knows about his brother's crush on their friend Bea, although a photo near the end of the theme song suggests it, the show has not shown any hints that he knows.
Milo is one of Bea's two best friends the other being his brother Oscar. The two seem to be good friends that help each other out or help Oscar when he's having a problem; although whenever Milo does something very reckless she sides with Oscar in scolding him ("Dollars and Fish"). It also seems like he may not spend much time with Bea by himself since during the episode "Big Fish" Milo made a huge deal out of the fact that Oscar was busy and couldn't hang out. Other times he may not acknowledge certain things that Bea does for him such as warn him throughout an entire episode about something or believe that Oscar was the one who said it ("Peopleing"). Milo and Bea were dating in "Bea Dates Milo " but soon break up, because they just what to remain friends.
Milo sees Chief as a role model due to the fact that he's the only fish that has been outside the tank more times than himself. He doesn't seem to care or know who Milo is though but is willing to help Oscar and Bea save him ("Peopleing").
Milo has a crush on Pamela the Hamster in "Hooray for Hamsterwood", basing their relationship on a lie, because Milo tells her he is also a hamster in order to keep her from finding out the truth.Though she discovers his secret, she doesn't appear mad, but states that she is really a gerbil. The two eventually break up before the episode "Bea Dates Milo".
He and Oscar have yet to have their last name revealed
Whenever Bea is playing a video game with him and Oscar, Oscar tells him to press the B button as the words "Hit B!" in which he misinterprets as "Hit Bea!" and he hits Bea instead of the B button on his controller (Two Clams in Love).
Milo refuses to celebrate any holiday if it is not associated with some kind of magical being such as Santa Claus, Easter Bunny, Happy Hanukkah Gefilte Fish and Kyle Massey ("Legend of the Earth Troll")