英语翻译How can you tell when a fish wants to eat Does a hungry

英语翻译
How can you tell when a fish wants to eat Does a hungry fish look the same as a full one
Dr.Smith trained (训练) her angel Fish (神仙鱼) to ring a bell when they wanted food.For a few days she didn't feed (give food to ) them at all.They were very hungry.Then she tied a little bell to one end of a string (绳子).She tied food to the other end and put it in the water.When the fish ate,the bell rang.
This went on for a few days.The fish ate the food,and the bell rang.Then Dr.Smith put the string into the water without food.The fish bit (咬) at the empty string and the bell rang.Every time they did this,Dr.Smith gave them food.Soon the fish had learned to pull the string and ring the bell when they were hungry.Have you ever seen fish with their own dinner bell