Iodine is an essential micronutrient for elasmobranchs in order to prevent goiter. Preventing goiter requires bioavailable iodide: either oral iodide or maintaining adequate aquarium water iodide concentrations. The objective of this study was to determine how oral and water supplementation affected iodine (I₂) and iodide (I⁻) concentrations in artificial seawater aquaria housing captive white-spotted bamboo sharks (Chiloscyllium plagiosum). Daily water samples were collected and free iodine (I₂) was determined using ultraviolet-absorbance spectrophotometry (a relatively simple in-house assay) and total iodide (I⁻) via liquid chromatography (a more time- and expertise-intense quantification method) to learn the effects of supplementation. One water system received iodine and iodide supplementation in the form of 5% Lugol's iodine solution added directly to the water, while a second water system received no supplementation. In addition, one tank of sharks in each water system received oral iodide supplementation. Results indicated that oral supplementation provides greater increases in water concentrations of bioavailable iodide (I⁻) than direct water supplementation. In addition, the chromatographic results suggested that iodide is present in higher concentrations in the systems not receiving water supplementation. Increased iodide concentrations were detected in water samples after water changes and after oral iodide supplementation was administered, but total iodine (I₂) concentration changes were not detectable within the same time frame.