behavior_packs/vanilla/spawn_rules/squid.json

{
  "format_version": "1.8.0",
  "minecraft:spawn_rules": {
    "description": {
      "identifier": "minecraft:squid",
      "population_control": "animal"
    },
    "conditions": [
      {
        "minecraft:spawns_on_surface": {},
        "minecraft:spawns_underwater": {},

        "minecraft:weight": {
          "default": 10
        },
        "minecraft:density_limit": {
          "surface":4
        },
        "minecraft:herd": {
          "min_size":2,
          "max_size":4
        },
        
        "minecraft:biome_filter": { 
          "any_of": [
            { "test": "has_biome_tag", "operator": "==", "value": "ocean" },
            { "test": "has_biome_tag", "operator": "==", "value": "river" }
          ]
        }

      }
    ]
  }
}