This mod expands your F3 screen to indicate whether you're in a slime-spawning area. It takes both slime chunks and swamps into account, and also checks the height. In swamps, the mod will also tell you the effect of the lunar phase on the slime spawn rate. Additionally, it displays the numeric world seed in SSP.
Since Minecraft 1.6.1, there are two different versions of this mod:
Vanilla Mod (JAR Mod)
Only provides the functionality described above. Use this one if you don't want to install Forge. It does not work in SMP and it may cause conflicts with other mods that aren't explicitly supported (see download description). Unlike before 1.6.1, there will only be a single download which should work with or without any of the supported mods.
This version can also be used in SMP. By default it will only react to swamp biomes. To enable slime chunk detection in SMP, you can either install this mod on the server as well (requires forge server), or manually set the seed in the config file (usually at
When installed on a server, the mod will not expose the map seed. It will only tell the clients with this mod installed whether or not the chunks around them are slime chunks. Thus, you won't be able to see the map seed in SMP with this mod, even if it'srunning on the server.