Horrid Henry's Aquarium is a episode in Series 1
Fishy fun at the aquarium as Dad takes Henry, Peter and Margaret for a day out.
Henry and his family were eating when Mum surprised the boys a trip to the Aquarium and Dad was taking them but when they got the car, they saw Margaret. Dad told them that she's coming along because her mum's at the dentist and Henry yells "Noooo!!".
Inside, Dad went to buy some tickets while Henry, Peter and Margaret look around and saw sea creatures. Then Captain Push-Me-Button comes and says to them answer his questions and win a prizes. Henry and Margaret augured about of them going to win. Margaret pushes the button and gets a piece of paper with questions and Henry did it too but then the robot goes out of control. The Policeman tells Henry not to touch anything but he press it again and gets a list of questions so did Peter. The robot throw his sword up and cuts the rope and a shark lands on the Policeman.
Margaret and Henry grabbed their tickets from Dad leaving him and Peter to go get a drink and catch up later. Meanwhile, Both Henry and Margaret were busying answering question. Henry finds an octopus and scares it away. Dad and Peter saw black ink so they called the octopus and walks off. The policeman says "What are you looking at?" to it and swims away.
Henry heard Margaret saying the answer of an octopus and writes it down but then The policeman finds him and makes a run for it. Henry was on the ship but he lowers the net and traps the policeman. Dad and Peter thought it was an octopus again but not the policeman calling for help.
Margaret was counting fish when the policeman interrupts her so he walks away and Henry comes out hearing her counting fish again. Later Henry and Margaret were finished and raced each other but the policemen follows them. Margaret told Henry to give her his shoe and she throws it in the water, The policemen saw it and dives in. The two of them argued when suddenly the policeman finds them. He was covered in seaweed and couldn't reach them and gets slides away to the exit. Henry grabs his shoes and while he and Margaret argued, Peter puts his paper into the robot declared him the winner.
Peter had two tickets to the Dingy Dungeon and asked Dad to come with him and he agreed. In the end, Henry and Margaret shouted "It's not fair!".
- This is one of the only six episode where Horrid Henry and Moody Margaret both lose throughout the episode, the others are (Horrid Henry's School Fair, Horrid Henry Gets Rich Quick, Horrid Henry and the Secret Club, Horrid Henry Gets A Job, Perfect Peter Popstar and Horrid Henry on TV.
- Henry's Mum is the first one to surprise Henry and Peter with a Trip Second is Prissy Polly with the trip to the Cinema in Horrid Henry Goes to the Movies.