IMoO/loot_tables/entities/drowned_equipment.json

{
  "pools": [
    {
      "rolls": 1,
      "conditions": [
        {
          "condition": "random_chance",
          "chance": 0.01
        }
      ],
      "entries": [
        {
          "type": "item",
          "name": "minecraft:fishing_rod",
          "weight": 5
        }
      ]
    },
    {
      "rolls": 1,
      "conditions": [
        {
          "condition": "random_chance",
          "chance": 0.08
        }
      ],
      "entries": [
        {
          "type": "item",
          "name": "minecraft:nautilus_shell",
          "weight": 5
        }
      ]
    }
  ]
}