Several techniques can be used to identify individual amphibians.
Selection depends on the species and the developmental stage.
Ideally, the system of choice would allow identification of individual animals at all stages of development from the time of fertilization through larval and postmetamorphic development. However, aside from isolation in individual enclosures, no system adequate to accomplish this objective is available. In practice, a clutch of eggs or a shipment of animals may be given a serial identification number such as 35,000 with subsequent numbers in the series reserved in proportion to the number of clutch or shipment members to which individual numbers will be assigned. As animals are assigned for specific experimental purposes, the experimental group or individual may be given numbers from among those reserved. Identification numbers may be written in waterproof ink on waterproof labels that, when appropriate, may be easily transferred from one enclosure to another.