Algal or Planktonic Fish Poisonings: Fish poisoning can result from the ingestion of fish or shellfish that have fed upon algae toxic to human beings. Paralytic shellfish poisoning is caused by ingestion of shellfish such as scallops, clams and mussels, which have consumed toxic dinoflagellates. Symptoms appear within 10min after ingestion and include gastrointestinal distress, parasthesia of the lips and fingertips followed by ataxia, muscular non-coordination and ascending paralysis. Death may occur within 2 to 12 hours from cardiovascular collapse or respiratory failure. The human lethal dose of toxin is considered to be 3 to 4 mg.