diff --git a/python/ray/rllib/ddpg/ddpg.py b/python/ray/rllib/ddpg/ddpg.py
index abd9f3d81..9a93e57c1 100644
--- a/python/ray/rllib/ddpg/ddpg.py
+++ b/python/ray/rllib/ddpg/ddpg.py
@@ -14,10 +14,14 @@ OPTIMIZER_SHARED_CONFIGS = [
 
 DEFAULT_CONFIG = {
     # === Model ===
-    # Hidden layer sizes of the policy networks
+    # Hidden layer sizes of the policy network
     "actor_hiddens": [64, 64],
-    # Hidden layer sizes of the policy networks
+    # Hidden layers activation of the policy network
+    "actor_hidden_activation": "relu",
+    # Hidden layer sizes of the critic network
     "critic_hiddens": [64, 64],
+    # Hidden layers activation of the critic network
+    "critic_hidden_activation": "relu",
     # N-step Q learning
     "n_step": 1,
     # Config options to pass to the model constructor
diff --git a/python/ray/rllib/ddpg/ddpg_policy_graph.py b/python/ray/rllib/ddpg/ddpg_policy_graph.py
index 870c5bcec..34aa9682b 100644
--- a/python/ray/rllib/ddpg/ddpg_policy_graph.py
+++ b/python/ray/rllib/ddpg/ddpg_policy_graph.py
@@ -26,11 +26,13 @@ class PNetwork(object):
     """Maps an observations (i.e., state) to an action where each entry takes
     value from (0, 1) due to the sigmoid function."""
 
-    def __init__(self, model, dim_actions, hiddens=[64, 64]):
+    def __init__(
+            self, model, dim_actions, hiddens=[64, 64], activation="relu"):
         action_out = model.last_layer
+        activation = tf.nn.__dict__[activation]
         for hidden in hiddens:
             action_out = layers.fully_connected(
-                action_out, num_outputs=hidden, activation_fn=tf.nn.relu)
+                action_out, num_outputs=hidden, activation_fn=activation)
         # Use sigmoid layer to bound values within (0, 1)
         # shape of action_scores is [batch_size, dim_actions]
         self.action_scores = layers.fully_connected(
@@ -69,11 +71,14 @@ class ActionNetwork(object):
 
 
 class QNetwork(object):
-    def __init__(self, model, action_inputs, hiddens=[64, 64]):
+    def __init__(
+            self, model, action_inputs,
+            hiddens=[64, 64], activation="relu"):
         q_out = tf.concat([model.last_layer, action_inputs], axis=1)
+        activation = tf.nn.__dict__[activation]
         for hidden in hiddens:
             q_out = layers.fully_connected(
-                q_out, num_outputs=hidden, activation_fn=tf.nn.relu)
+                q_out, num_outputs=hidden, activation_fn=activation)
         self.value = layers.fully_connected(
             q_out, num_outputs=1, activation_fn=None)
 
@@ -128,13 +133,15 @@ class DDPGPolicyGraph(TFPolicyGraph):
             return QNetwork(
                 ModelCatalog.get_model(obs, 1, config["model"]),
                 actions,
-                config["critic_hiddens"]).value
+                config["critic_hiddens"],
+                config["critic_hidden_activation"]).value
 
         def _build_p_network(obs):
             return PNetwork(
                 ModelCatalog.get_model(obs, 1, config["model"]),
                 dim_actions,
-                config["actor_hiddens"]).action_scores
+                config["actor_hiddens"],
+                config["actor_hidden_activation"]).action_scores
 
         def _build_action_network(p_values, stochastic, eps):
             return ActionNetwork(
diff --git a/python/ray/rllib/models/catalog.py b/python/ray/rllib/models/catalog.py
index 61b31f708..0da5dc2db 100644
--- a/python/ray/rllib/models/catalog.py
+++ b/python/ray/rllib/models/catalog.py
@@ -24,10 +24,8 @@ MODEL_CONFIGS = [
     # === Built-in options ===
     "conv_filters",  # Filter configuration
     "conv_activation",  # Nonlinearity for built-in convnet
-
     "fcnet_activation",  # Nonlinearity for fully connected net (tanh, relu)
     "fcnet_hiddens",  # Number of hidden layers for fully connected net
-
     "dim",  # Dimension for ATARI
     "grayscale",  # Converts ATARI frame to 1 Channel Grayscale image
     "zero_mean",  # Changes frame to range from [-1, 1] if true
diff --git a/python/ray/rllib/models/fcnet.py b/python/ray/rllib/models/fcnet.py
index ce516f1c7..3f5bcabf6 100644
--- a/python/ray/rllib/models/fcnet.py
+++ b/python/ray/rllib/models/fcnet.py
@@ -14,7 +14,6 @@ class FullyConnectedNetwork(Model):
 
     def _build_layers(self, inputs, num_outputs, options):
         hiddens = options.get("fcnet_hiddens", [256, 256])
-
         activation = get_activation_fn(options.get("fcnet_activation", "tanh"))
 
         with tf.name_scope("fc_net"):