Fluidlogged API 1.12.2 Forge Mod Overview
A mod that adds 1.13 Waterlogging/Fluidlogging support to 1.12.2. By default only Stairs, Slabs, Fences, Walls, Fence Gates, End Rods and a few others work. The rest need to be added on a Mod Development level, not a config.
Mod Link:
https://www.curseforge.com/minecraft/...
Other mod I mentioned that is for 1.14+ Fabric
https://www.curseforge.com/minecraft/...