Нужно! написать письмо you have received a letter from your english-speaking pen friend arthur. i am so happy to receive your congratulations on my birthday! it`s unbelievable but my dream has come true! my parents have gifted me with an aquarium! tomorrow i`m going to the zoo shop to buy fish! my sister has promised to help me choose. what pets have you got? what problems do you think i may come across? any advice would be very useful. what pet would be better for me? best wishes, arthur.

Hello Arthur. I'm very happy about you . Fish is a great choise , but what kind of fish do you want to get exactly ? You know i prefer small fishes because they are so kind ! Well, about my pets... I have two dogs : Charly and Bony , i like them . Its so funny to see how they are trying to destroy your slippers, you know . 
I think the main for is to find some free time to look after your pets. I know that you are very busy with your school and football , but you have to find some time to give some food for your fish. 
I think you should to buy a dog or may be a cat because it will be easier to look after them , in my view ofcourse. 
So let me know what kind of pet you've choosen . 
Best wishes,
(your name)