The cadets that are seen include (from left to right):
A male purple fish.
A female light blue/teal fish who is thin.
A very short chubbyish male brownish-yellowish fish.
A tall male dark yellow fish.
And a tall female pink fish (who is about the same height as the male dark yellow fish).
The Milkshake Academy Cadets are skilled, unlike SpongeBob. They are able to perform any task Captain Frostymug tells them to do with ease. They were first seen just outside the Milkshake Academy, jogging with large jugs of ice cream on their backs. When Frostymug singled SpongeBob out, asking what he was holding (which was an ice cream scooper), SpongeBob said it was an "ice cream spatula," and all five of the cadets laughed at SpongeBob. Frostymug then told a short story on how he was going to turn them into milkshake machines, and told them to get to their milkshake stations. All five cadets were successful at blending up a milkshake, but SpongeBob wasn't too lucky, as he didn't know where the control panels were. Frostymug then had the purple cadet tell SpongeBob where the real controls were. SpongeBob then blended up a milkshake, although it ended up smashing into Frostymug's eye.
The Cadets then followed Frostymug into the Shake Simulator room, where he decided to put SpongeBob into the machine. Frostymug set it to the highest setting, much to the horror of some of the cadets. SpongeBob ended up having fun in the machine, greatly upsetting Frostymug. Frostymug then lost it, and asked the cadets if they had any tips to teach SpongeBob. The shortest cadet implied that Frostymug was better off "teaching a hunk of coral." All five cadets laughed and SpongeBob stormed off, saying that he would show them. The cadets were then put through a series of tests, including cherry shooting range, and even volleyball. They all managed to complete their tasks, but SpongeBob was once again unsuccessful in doing this. The Milkshake Academy Cadets were seen for the last time at a milkshake ceremony, as Captain Frostymug handed them all their milkshake licenses. They all left the Academy excited to be qualified milkshakers, but SpongeBob was left without one of his own (though he did receive one at the end).
Out of the 5 cadets, only 3 had speaking roles.
However, all of them laughed, but that is not considered speaking.