"foul fish" meaning in English

{
  "forms": [
    {
      "form": "foul fish",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "foul fish"
      },
      "expansion": "foul fish (plural foul fish)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "English entries with incorrect language header",
          "parents": [
            "Entries with incorrect language header",
            "Entry maintenance"
          ],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with 1 entry",
          "parents": [],
          "source": "w"
        },
        {
          "kind": "other",
          "name": "Pages with entries",
          "parents": [],
          "source": "w"
        }
      ],
      "examples": [
        {
          "ref": "1864, The Fishermans Magazine and Review, volume 1, page 331:",
          "text": "I am aware that many anglers would disdain to kill foul fish, but am also aware that many others think it, as they say, first-rate sport.",
          "type": "quote"
        }
      ],
      "glosses": [
        "A kelt or salmon, which, having spawned, still remains in the fresh water before effecting its annual migration to the sea."
      ],
      "id": "en-foul_fish-en-noun-vITX7SI-",
      "links": [
        [
          "kelt",
          "kelt"
        ],
        [
          "salmon",
          "salmon"
        ],
        [
          "spawn",
          "spawn"
        ],
        [
          "migration",
          "migration"
        ]
      ]
    }
  ],
  "word": "foul fish"
}

{
  "forms": [
    {
      "form": "foul fish",
      "tags": [
        "plural"
      ]
    }
  ],
  "head_templates": [
    {
      "args": {
        "1": "foul fish"
      },
      "expansion": "foul fish (plural foul fish)",
      "name": "en-noun"
    }
  ],
  "lang": "English",
  "lang_code": "en",
  "pos": "noun",
  "senses": [
    {
      "categories": [
        "English countable nouns",
        "English entries with incorrect language header",
        "English lemmas",
        "English multiword terms",
        "English nouns",
        "English terms with quotations",
        "Pages with 1 entry",
        "Pages with entries"
      ],
      "examples": [
        {
          "ref": "1864, The Fishermans Magazine and Review, volume 1, page 331:",
          "text": "I am aware that many anglers would disdain to kill foul fish, but am also aware that many others think it, as they say, first-rate sport.",
          "type": "quote"
        }
      ],
      "glosses": [
        "A kelt or salmon, which, having spawned, still remains in the fresh water before effecting its annual migration to the sea."
      ],
      "links": [
        [
          "kelt",
          "kelt"
        ],
        [
          "salmon",
          "salmon"
        ],
        [
          "spawn",
          "spawn"
        ],
        [
          "migration",
          "migration"
        ]
      ]
    }
  ],
  "word": "foul fish"
}