Why does the program close when I click the button?

Could someone tell me why the program closes after clicking the button?

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import org.w3c.dom.Text;

public class MainActivity extends AppCompatActivity {


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_main);

        //reference to xml widgets
        TextView FishText = (TextView) findViewById(R.id.FishText);
        TextView DogText = (TextView) findViewById((R.id.DogText));
        Button ChangeNameButton = (Button) findViewById(R.id.ChangeNameButton);

        final String animals[] = new String[5];

    }






        public void ChangeFish(){
            String [] animals = {"Dog","Cat","Rat","Horse","Mouse"};
        final TextView FishText = (TextView) findViewById(R.id.FishText);
            for(int contador = 0;contador<5;contador++) {
                FishText.setText(animals[contador]);
            }



            }
    }

<TextView
    android:id="@+id/textView2"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginLeft="16dp"
    android:layout_marginTop="41dp"
    android:text="This words will change if your press the button!"
    android:textSize="18dp"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    tools:layout_constraintLeft_creator="1"
    tools:layout_constraintTop_creator="1" />

<TextView
    android:id="@+id/FishText"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginLeft="162dp"
    android:layout_marginStart="162dp"
    android:layout_marginTop="60dp"
    android:text="Fish"
    android:textColor="#C12B2B"
    android:textSize="20sp"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintTop_toBottomOf="@+id/textView2"
    tools:layout_constraintLeft_creator="1"
    tools:layout_constraintTop_creator="1" />

<Button
    android:id="@+id/ChangeNameButton"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:onClick="ChangeFish"
    android:text="Click me to change the word"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    tools:layout_constraintBottom_creator="1"
    tools:layout_constraintLeft_creator="1"
    tools:layout_constraintRight_creator="1"
    tools:layout_constraintTop_creator="1" />

<TextView
    android:id="@+id/DogText"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginTop="12dp"
    android:text="Dog"
    android:textSize="20sp"
    app:layout_constraintRight_toRightOf="@+id/FishText"
    app:layout_constraintTop_toBottomOf="@+id/FishText"
    tools:layout_constraintRight_creator="1"
    tools:layout_constraintTop_creator="1" /><![CDATA[

;
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintVertical_bias="0.271"/>