diff --git a/app/services/activitypub/fetch_all_replies_service.rb b/app/services/activitypub/fetch_all_replies_service.rb
index 19fae824dff495..cba476ab46c30c 100644
--- a/app/services/activitypub/fetch_all_replies_service.rb
+++ b/app/services/activitypub/fetch_all_replies_service.rb
@@ -10,7 +10,7 @@ def call(collection_or_uri, allow_synchronous_requests: true, request_id: nil)
     @allow_synchronous_requests = allow_synchronous_requests
     @filter_by_host = false
 
-    @items = collection_items(collection_or_uri)
+    @items = collection_items(collection_or_uri, fetch_all: true)
     @items = filtered_replies
     return if @items.nil?
 
@@ -25,6 +25,8 @@ def filtered_replies
     return if @items.nil?
 
     # find all statuses that we *shouldn't* update the replies for, and use that as a filter
+    # Typically we assume this is smaller than the replies we *should* fetch,
+    # so we minimize the number of uris we should load here.
     uris = @items.map { |item| value_or_id(item) }
     dont_update = Status.where(uri: uris).shouldnt_fetch_replies.pluck(:uri)
 
diff --git a/app/services/activitypub/fetch_replies_service.rb b/app/services/activitypub/fetch_replies_service.rb
index 0dcdb638e1339e..2963f616e2882b 100644
--- a/app/services/activitypub/fetch_replies_service.rb
+++ b/app/services/activitypub/fetch_replies_service.rb
@@ -5,6 +5,8 @@ class ActivityPub::FetchRepliesService < BaseService
 
   # Limit of fetched replies
   MAX_REPLIES = 5
+  # Limit when fetching all (to prevent infinite fetch attack)
+  FETCH_ALL_MAX_REPLIES = 500
 
   def call(parent_status, collection_or_uri, allow_synchronous_requests: true, request_id: nil, filter_by_host: true)
     @account = parent_status.account
@@ -21,7 +23,7 @@ def call(parent_status, collection_or_uri, allow_synchronous_requests: true, req
 
   private
 
-  def collection_items(collection_or_uri)
+  def collection_items(collection_or_uri, fetch_all: false)
     collection = fetch_collection(collection_or_uri)
     return unless collection.is_a?(Hash)
 
@@ -39,8 +41,8 @@ def collection_items(collection_or_uri)
 
       all_items.concat(as_array(items))
 
-      # Quit early if we are not fetching all replies
-      break if all_items.size >= MAX_REPLIES
+      # Quit early if we are not fetching all replies or we've reached the absolute max
+      break if (!fetch_all && all_items.size >= MAX_REPLIES) || (all_items.size >= FETCH_ALL_MAX_REPLIES)
 
       collection = collection['next'].present? ? fetch_collection(collection['next']) : nil
     end
diff --git a/app/workers/activitypub/fetch_all_replies_worker.rb b/app/workers/activitypub/fetch_all_replies_worker.rb
index af2cf40e91ca1d..222736224b2439 100644
--- a/app/workers/activitypub/fetch_all_replies_worker.rb
+++ b/app/workers/activitypub/fetch_all_replies_worker.rb
@@ -11,7 +11,7 @@ class ActivityPub::FetchAllRepliesWorker
 
   sidekiq_options queue: 'pull', retry: 3
 
-  # Global max replies to fetch per request
+  # Global max replies to fetch per request (all replies, recursively)
   MAX_REPLIES = 1000
 
   def perform(parent_status_id, current_account_id = nil, options = {})
@@ -20,21 +20,21 @@ def perform(parent_status_id, current_account_id = nil, options = {})
     @current_account = @current_account_id.nil? ? nil : Account.find(@current_account_id)
     Rails.logger.debug { "FetchAllRepliesWorker - #{parent_status_id}: Fetching all replies for status: #{@parent_status}" }
 
-    all_replies = get_replies(@parent_status.uri, options)
-    got_replies = all_replies.length
-    until all_replies.empty? || got_replies >= MAX_REPLIES
-      next_reply = all_replies.pop
+    uris_to_fetch = get_replies(@parent_status.uri, options)
+    fetched_uris = uris_to_fetch
+    until uris_to_fetch.empty? || fetched_uris.length >= MAX_REPLIES
+      next_reply = uris_to_fetch.pop
       next if next_reply.nil?
 
-      new_replies = get_replies(next_reply, options)
-      next if new_replies.nil?
+      new_reply_uris = get_replies(next_reply, options)
+      next if new_reply_uris.nil?
 
-      got_replies += new_replies.length
-      all_replies.concat(new_replies)
+      uris_to_fetch.concat(new_reply_uris)
+      fetched_uris.concat(new_reply_uris)
     end
 
-    Rails.logger.debug { "FetchAllRepliesWorker - #{parent_status_id}: fetched #{got_replies} replies" }
-    got_replies
+    Rails.logger.debug { "FetchAllRepliesWorker - #{parent_status_id}: fetched #{fetched_uris.length} replies" }
+    fetched_uris
   end
 
   private