Set up Critters and Companions on Minecraft

Critters and Companions is a vanilla-style creature mod that fills the overworld with new animals, such as otters, ferrets, koi fish, red pandas and a range of tameable insects. This guide covers a Fabric or NeoForge server on Minecraft 1.21.1. Every player needs the mod too.

Checked against Critters and Companions 2.7.0 on Fabric and NeoForge, Minecraft 1.21.1, October 2026.

What you need

• Fabric or NeoForge on Minecraft 1.21.1. Version 2.7.0 declares exactly 1.21.1. Minecraft 1.20.1 has its own file, 2.7.1, for Forge and for Fabric.
• Java 21. JAR Manager shows "Runs on Java 21. We switch it for you." for 1.21.1.
• Libraries. Fabric needs Fabric API, Architectury API, GeckoLib and YetAnotherConfigLib (YACL), and the Fabric file's own metadata lists all four. NeoForge needs Architectury API and GeckoLib; its metadata marks YACL as client-side only. Modrinth lists YACL as required for both, so the install window may offer it either way.
• The mod and the same libraries on each player's computer. See Join a modded server from your launcher.

Switch the server to 1.21.1

1. Open JAR Manager, under More in the left rail.
2. Set Server software to Fabric or NeoForge and Minecraft version to 1.21.1, then press Apply change.
3. Leave Take a backup first ticked, press and hold Confirm & reinstall, and wait for the console to finish.

Your world is kept, but the screen warns that configuration files may be reset. See Change your Minecraft version or mod loader.

Install it

1. Open the Mods tab under Content and leave the Modrinth source chip selected.
2. Search for Critters and Companions and press Install on the one by Joo5h.
3. A window titled "Needs N more add-ons" names the libraries the server is missing. Press Install all to add them in one go. Trinkets and Mod Menu may appear as optional extras on Fabric; leave them unticked unless you want them.
4. Go to Console, press Start and accept the EULA prompt the first time.

The mod's page and default spawn config say the animals live in particular places. Otters spawn in rivers, ferrets in plains and forests, red pandas in jungles, dumbo octopuses in oceans, and shima enaga in snowy biomes. Many can be tamed with a food, such as raw rabbit for a ferret, seeds for a shima enaga or sweet berries for a red panda.

Change where animals spawn

The mod writes config/crittersandcompanions-common.json5 when it first runs. Open it in the File Manager and press Edit. Its main sections are spawning, necklace and grapplingHook:

• Under spawning, every animal has a list of entries. Each names a biome or biome tag, a spawn weight, and a minimum and maximum group size.
• preventMonsterSpawnsInLushCaves is false by default. Set it to true to stop monsters spawning in lush caves. The mod notes that this change takes effect after a restart.

Press Save and restart the server.

Common problems

• The server stops at start and names yet_another_config_lib_v3. YACL is required on Fabric. Search for YetAnotherConfigLib in the Mods tab and install it.
• It names geckolib or architectury. Install the missing library from the same tab.
• Players cannot join. Their Critters and Companions file and libraries must match. Use Export for players on the Mods tab to hand them what they need.