Tagging seahorses

UK conservationists are concerned about the long-term survival of seahorses because the creatures live among coral reefs, seagrass beds and mangroves, which are among the most threatened habitats on the planet.
To tag seahorses, a UK team has developed a Visible Implant Fluorescent Elastomer (VIFE), a fluorescent polymer that is biologically compatible with seahorses. The liquid is injected under the skin in a position unique to each seahorse, allowing the team to identify individuals.

Read more about this on the BBC website.