The present invention relates to a sampling device 100. The sampling device 100 comprises a separate compartment 110 that is ejected creating an increased space or volume for a sample to be stored. The sampling device 100 of the present invention is suitable for collecting a sample in an aquaculture environment, enclosed system or in the gastrointestinal tract of a human or an animal. The invention also relates to a method of orally administering the device 100 to an animal and recovering the device 100 and/or separate compartment 110 to carry out analysis on the collected sample for diagnosing the health of the gastrointestinal tract and determining nutrient absorption and digestibility.