Project
K's Koi Mod
A self-built Minecraft Forge mod that adds breeding, schooling koi fish.
A standalone Forge 1.16.5 mini-mod that adds koi fish to Minecraft. Koi spawn in water, school toward a player holding craftable pellets, and breed along a nine-colour ladder. Built end to end as a proof-of-workflow for a larger mod project, and compiled to a loadable jar.
In-game screenshot (placeholder):
Why
I wanted to learn Java game modding by taking the whole toolchain end to end on the simplest useful creature: idea, to 3D model, to texture, to a live entity swimming in-game. The koi is deliberately small in scope. Its job is to de-risk the pipeline for a larger mod, so that the harder mobs are just more of a pattern I have already run once.
What it does
- Adds a koi entity that swims and spawns naturally in water, weighted into river and ocean spawn pools alongside vanilla fish.
- Koi school toward a nearby player holding craftable Koi Pellets, using a swimmer-safe follow behaviour.
- Breeding runs along a nine-colour ladder (black through violet), with three hand-made patterns per colour and a breeding cooldown.
- Ships the supporting items: Koi Pellets with a crafting recipe, a koi bucket, and a spawn egg.
How it is built
The mod is written in Java 8 against Minecraft Forge 1.16.5 (ForgeGradle 5, official Mojang mappings). It follows the standard Forge pattern: deferred registries for the entity and items, an entity class with data-synced colour and NBT persistence, a custom goal for the pellet lure, and a client-side model and renderer. The 3D model was made in Blockbench. It compiles cleanly to a reobfuscated mod jar that loads in a dev client, with the koi visible, spawning, swimming, and breeding.
Stack
- Language and platform: Java 8, Minecraft Forge 1.16.5, ForgeGradle 5.
- Modeling and art: Blockbench model, hand-made colour and pattern textures.
- Build: Gradle, producing a loadable mod jar.