diff --git a/src/robofish/io/__init__.py b/src/robofish/io/__init__.py
index 4038229f4491f8863b8204c3658f6b448892f8f9..5b054c2fb71018dd23ceb315d83bf83f51cc1cac 100644
--- a/src/robofish/io/__init__.py
+++ b/src/robofish/io/__init__.py
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: LGPL-3.0-or-later
 
 """
-The Python package <a href="https://git.imp.fu-berlin.de/bioroboticslab/robofish/io">robofish.io</a> provides a simple interface to create, load, modify, and inspect files containing tracks of swarms.
+The Python package <a href="https://git.imp.fu-berlin.de/bioroboticslab/robofish/io">robofish.io</a> provides a simple interface to create, load, modify, and inspect files containing world information and movement tracks of entities (organisms, robots, obstacles,...).
 The files are saved in the `.hdf5` format and following the [Track Format Specification](https://git.imp.fu-berlin.de/bioroboticslab/robofish/track_format/uploads/f76d86e7a629ca38f472b8f23234dbb4/RoboFish_Track_Format_-_1.0.pdf).
 
 .. include:: ../../../docs/index.md
diff --git a/src/robofish/io/file.py b/src/robofish/io/file.py
index c805381ab2782c0be5841ccc0a000b74f8eb87ea..14d2a4d1d3f2aec3253e84d6733c4ae3b6b6851a 100644
--- a/src/robofish/io/file.py
+++ b/src/robofish/io/file.py
@@ -315,7 +315,7 @@ class File(h5py.File):
 
         Args:
             TODO
-            category: the  of the entity. The canonical values are ['fish', 'robot', 'obstacle'].
+            category: the  of the entity. The canonical values are ['organism', 'robot', 'obstacle'].
             poses: optional two dimensional array, containing the poses of the entity (x,y,orientation_x, orientation_y).
             poses_rad: optional two dimensional containing the poses of the entity (x,y, orientation_rad).
             name: optional name of the entity. If no name is given, the  is used with an id (e.g. 'fish_1')
@@ -353,7 +353,7 @@ class File(h5py.File):
         """Creates multiple entities.
 
         Args:
-            category: The common category for the entities. The canonical values are ['fish', 'robot', 'obstacle'].
+            category: The common category for the entities. The canonical values are ['organism', 'robot', 'obstacle'].
             poses: three dimensional array, containing the poses of the entity.
             name: optional array of names of the entities. If no names are given, the category is used with an id (e.g. 'fish_1')
             outlines: optional array, containing the outlines of the entities, either a three dimensional common outline array can be given, or a four dimensional array.
diff --git a/tests/robofish/io/test_entity.py b/tests/robofish/io/test_entity.py
index 17fdcd259e49735c1cbea607ef2cd9ae67be5d7b..72dc5f7efe8a0ed1296a66f39473e575230dd123 100644
--- a/tests/robofish/io/test_entity.py
+++ b/tests/robofish/io/test_entity.py
@@ -6,9 +6,9 @@ import numpy as np
 def test_entity_object():
     sf = robofish.io.File(world_size_cm=[100, 100], frequency_hz=25)
     f = sf.create_entity("fish", positions=[[10, 10]])
-    assert type(f) == robofish.io.Entity
-    assert f.name == "fish_1"
-    assert f.attrs["category"] == "fish"
+    assert type(f) == robofish.io.Entity, "Type of entity was wrong"
+    assert f.name == "fish_1", "Name of entity was wrong"
+    assert f.attrs["category"] == "fish", "category was wrong"
     print(dir(f))
     print(f["positions"])
     assert type(f["positions"]) == h5py.Dataset