What It Does
Fluidlogged is a Forge and Fabric mod that lets you waterlog any block with any fluid, not just the handful of blocks Minecraft normally allows. It also lets fluids pass through blocks instead of stopping at the surface. Instead of relying on the game's blockstate system to track which blocks hold fluid, this mod keeps that fluid data separate, stored per chunk. The author says this approach cuts down on startup time and memory use when you've got a lot of mods installed, since blockstates are not being multiplied for every fluid combination.
Who It's For
This fits players and server owners who want builds with fluids in places vanilla rules block, like lava behind glass, decorative pools and fountains, or floods that move through structures. Because the mod is required on both the client and the server, it's a pack wide decision rather than something one player can add alone. It falls under Game Mechanics, Libraries and APIs, and Utility and Quality of Life, so working this into a mod pack list is reasonable, including as a shared dependency for other mods per the author's license terms.
Main Features
A good number of blocks that can't normally hold water become fluidloggable automatically, no setup needed. Real talk, if you don't want certain behavior, like fluid passing through blocks, you can turn it off in a config file, and changes there apply right away without a restart. There's also a /setfluid command that lets you place a fluid directly into any block, bypassing whatever the config allows. On Fabric, the mod needs YetAnotherConfigLib and Fabric API installed alongside it. The project page doesn't list the same requirement for Forge.
Compatibility and Status
Fluidlogged supports Forge and Fabric, on Minecraft 1.19, 1.19.1, 1.19.2, 1.19.3, 1.20, and 1.20.1. It's released under the MIT License. The author describes the mod as being in beta because it touches chunk loading and saving, meaning future versions could change how it works internally. One project page recommends backing up any world you care about before using it, even though it hasn't shown signs of instability. If you hit a conflict with another mod, the author asks that you report it directly rather than filing it against the other mod, since the fluid handling logic lives here. A built in API for other mods to hook into Fluidlogged's compatibility layer is planned but not available yet.
