The wonders of evolution: Tongue-eating louse (Cymothoa exigua). This parasite enters the fish's mouth (Lutjanus sp.), clings to the tongue's base and extracts all the blood until the tongue atrophies.. Then it replaces the fish's tongue by attaching its own body to the muscles of the tongue stub, and starts to feed on what the host eats; the fish can live normally, and there are even studies around the benefits that he could receive from this parasite. There are no risks to humans.
Aquatic Mexican Salamander! These fascinating little salamanders (axolotls) naturally retain their gills and remain aquatic throughout their life cycle, though they will metamorphize into terrestrials if injected with iodine. Wild axolotls are listed as critically threatened and are rapidly nearing extinction due to the urbanization of Mexico City, heavy pollution, and the recent introduction of non-native breeder fish which compete for sustaining plant life and kill the axolotl's young.