How to I draw a Background Bitmap to a canvas?

public class Fish extends View {
    Bitmap bitmap, mBackground;
    float x, y;

    public Fish(Context context) {
        super(context);
        bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.fish1);
        mBackground = BitmapFactory.decodeResource(getResources(), R.drawable.tank);

        x = 0;
        y = 0;
    }


    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        canvas.drawBitmap(mBackground, 0, 0, null);
        canvas.drawBitmap(bitmap, x, y, null);
        if (x < canvas.getWidth())
        {
            x += 10;
        }else{
            x = 0;
        }
        invalidate();


    }

            }