Mechanic

Mechanics are configured in realistic_fishing.json.
Start fishing - after the player has used the fishing rod. Takes random fish within the Range. Fish has 3 stages.

1. If the distance to the hook is more than 3 blocks. Then the fish swims at a speed of long_distance_speed.
2. If the distance to the hook is more than 0.5-3 blocks. Then the fish swims at a speed of middle_distance_speed.
3. If the distance to the hook is more than 0-0.5 blocks. Then the fish swims at a speed of short_distance_speed. Then the fish starts to bite. With a chance of catch_chance, the fish will be caught on the hook and the mini-game will begin. If the chance does not work, the fish swims back a little and stage 3 begins again.

Drop - the plugin analyzes what type of entity the player is trying to catch.

1. If the dropped drop corresponds to the material of the entity, then nothing changes.
2. If the drop you drop does not match the material of the entity fish and is in the black list of materials (Materials that are considered fish), then the drop is replaced. A new drop map is created, which includes all the fish that match the type of entity caught. If this fish is not in the custom drop map, then a fish item is generated.
3. If the item does not match the type of entity and is not contained in the black list (that is, a treasure or another item other than a fish fell out), then you get 2 awards. This fish that you caught and an additional treasure.

Summarizing these rules, we can conclude that the player will always get only the fish that he catches (the type of entity). The player may receive additional treasures if they come across in the mini-game itself (basic mechanics of LiteFish mini-games)

realistic_fishing.json

{
  "range": {
    "x": 10,
    "y": 10,
    "z": 10
  },
  "catch_chance": 20.0,
  "long_distance_speed": 0.1,
  "middle_distance_speed": 0.05,
  "short_distance_speed": 0.02
}

range - the range in which the fish will be lured
catch_chance - the chance that the fish will get hooked at stage 3