YOU SAID:

i have 100 fishes in a hat

INTO JAPANESE

私は帽子に100匹の魚を持っています

BACK INTO ENGLISH

I have 100 fish in my hat

INTO JAPANESE

帽子に100匹の魚がいます

BACK INTO ENGLISH

There are 100 fish in the hat

INTO JAPANESE

帽子には100匹の魚がいます

BACK INTO ENGLISH

There are 100 fish in the hat