Dry ice is solid carbon dioxide, a greenhouse gas set at a temperature of -80°C. It would obviously freeze fresh fish. The frozen fish would benefit, however, some carriers will not handle it as it is on the dangerous chemicals list. Why? Freezer burn from dry ice is worse than a fourth degree burn from heat and without a sealed, unbreakable, double insulated container is very risky to use. For the safety of both our customers and the drivers we don't use it.