diff --git a/Cargo.lock b/Cargo.lock
index 62665b1..872812e 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -435,6 +435,7 @@ dependencies = [
  "tempfile",
  "term_grid",
  "terminal_size",
+ "thiserror",
  "unicode-width",
  "url",
  "users",
diff --git a/Cargo.toml b/Cargo.toml
index 0f6807e..3e4421a 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -27,6 +27,7 @@ libc = "0.2.*"
 human-sort = "0.2.2"
 term_grid = "0.1.*"
 terminal_size = "0.1.*"
+thiserror = "1.0"
 chrono = "0.4.*"
 chrono-humanize = "0.1.*"
 unicode-width = "0.1.*"
diff --git a/src/app.rs b/src/app.rs
index 9a65fac..971d013 100644
--- a/src/app.rs
+++ b/src/app.rs
@@ -54,6 +54,8 @@ pub fn build() -> App<'static> {
             Arg::with_name("icon-theme")
                 .long("icon-theme")
                 .default_value("fancy")
+                .possible_value("fancy")
+                .possible_value("unicode")
                 .multiple_occurrences(true)
                 .takes_value(true)
                 .number_of_values(1)
diff --git a/src/flags/icons.rs b/src/flags/icons.rs
index 638c92e..fec9aac 100644
--- a/src/flags/icons.rs
+++ b/src/flags/icons.rs
@@ -96,7 +96,6 @@ pub enum IconTheme {
     Unicode,
     #[default]
     Fancy,
-    Custom(String),
 }
 
 impl IconTheme {
diff --git a/src/icon.rs b/src/icon.rs
index cb8b4f9..a23e9b6 100644
--- a/src/icon.rs
+++ b/src/icon.rs
@@ -4,7 +4,6 @@ use crate::theme::{icon::IconTheme, Theme};
 
 pub struct Icons {
     icon_separator: String,
-
     theme: Option<IconTheme>,
 }
 
@@ -16,11 +15,14 @@ impl Icons {
     pub fn new(tty: bool, when: IconOption, theme: FlagTheme, icon_separator: String) -> Self {
         let icon_theme = match (tty, when, theme) {
             (_, IconOption::Never, _) | (false, IconOption::Auto, _) => None,
-            (_, _, FlagTheme::Fancy) => Some(IconTheme::default()),
+            (_, _, FlagTheme::Fancy) => {
+                if let Ok(t) = Theme::from_path::<IconTheme>("icons") {
+                    Some(t)
+                } else {
+                    Some(IconTheme::default())
+                }
+            },
             (_, _, FlagTheme::Unicode) => Some(IconTheme::unicode()),
-            (_, _, FlagTheme::Custom(ref file)) => {
-                Some(Theme::from_path::<IconTheme>(file).unwrap_or_default())
-            }
         };
 
         Self {
diff --git a/src/theme.rs b/src/theme.rs
index c284193..ae0cdcc 100644
--- a/src/theme.rs
+++ b/src/theme.rs
@@ -1,9 +1,11 @@
 pub mod color;
 pub mod icon;
 
-use serde::{de::DeserializeOwned, Deserialize};
-use std::fs;
 use std::path::Path;
+use std::{fs, io};
+
+use serde::{de::DeserializeOwned, Deserialize};
+use thiserror::Error;
 
 use crate::config_file;
 use crate::print_error;
@@ -20,49 +22,53 @@ pub struct Theme {
     pub icon: IconTheme,
 }
 
+#[derive(Error, Debug)]
+pub enum Error {
+    #[error("Theme file not existed")]
+    NotExisted(#[from] io::Error),
+    #[error("Theme file format invalid")]
+    InvalidFormat(#[from] serde_yaml::Error),
+    #[error("Theme file path invalid {0}")]
+    InvalidPath(String),
+    #[error("Unknown Theme error")]
+    Unknown(),
+}
+
 impl Theme {
     /// This read theme from file,
     /// use the file path if it is absolute
     /// prefix the config_file dir to it if it is not
-    pub fn from_path<D: DeserializeOwned>(file: &str) -> Option<D> {
+    pub fn from_path<D: DeserializeOwned>(file: &str) -> Result<D, Error> {
         let real = if let Some(path) = config_file::Config::expand_home(file) {
             path
         } else {
             print_error!("Not a valid theme file path: {}.", &file);
-            return None;
+            return Err(Error::InvalidPath(file.to_string()));
         };
         let path = if Path::new(&real).is_absolute() {
             real
         } else {
-            config_file::Config::config_file_path()?
-                .join("themes")
-                .join(real)
+            match config_file::Config::config_file_path() {
+                Some(p) => p.join("themes").join(real),
+                None => return Err(Error::InvalidPath("config home not existed".into())),
+            }
         };
-        match fs::read(&path.with_extension("yaml")) {
-            Ok(f) => match Self::with_yaml(&String::from_utf8_lossy(&f)) {
-                Ok(t) => Some(t),
-                Err(e) => {
-                    print_error!("Theme file {} format error: {}.", &file, e);
-                    None
-                }
-            },
-            Err(_) => {
-                // try `yml` if `yaml` extension file not found
-                match fs::read(&path.with_extension("yml")) {
-                    Ok(f) => match Self::with_yaml(&String::from_utf8_lossy(&f)) {
-                        Ok(t) => Some(t),
-                        Err(e) => {
-                            print_error!("Theme file {} format error: {}.", &file, e);
-                            None
-                        }
-                    },
+
+        // try `yml` if `yaml` extension file not found or error
+        let mut err: Error = Error::Unknown();
+        for ext in ["yaml", "yml"] {
+            match fs::read(&path.with_extension(ext)) {
+                Ok(f) => match Self::with_yaml(&String::from_utf8_lossy(&f)) {
+                    Ok(t) => return Ok(t),
                     Err(e) => {
-                        print_error!("Not a valid theme: {}, {}.", path.to_string_lossy(), e);
-                        None
+                        err = Error::from(e);
                     }
-                }
+                },
+                Err(e) => err = Error::from(e),
             }
         }
+
+        Err(err)
     }
 
     /// This constructs a Theme struct with a passed [Yaml] str.