Otters have potent musk glands and "spraint" (smear) their feces to mark territory, creating a pervasive and unpleasant smell.

If you find a legal pathway, be prepared for extreme lifestyle changes and high costs:

The international trade of Asian small-clawed and smooth-coated otters is prohibited for commercial purposes under CITES Appendix I . Why Otters Make Challenging "Pets"

Meet the Asian Small-Clawed Otter, an Adorable and Social Carnivore

Owning a pet otter is in many regions, including the UK and most of the U.S.. While their "cute" social media presence has fueled a global demand, experts from WebMD and the National Zoo strongly advise against keeping them as pets because they are wild animals that do not thrive in domestic settings. Legal and Ethical Status