Aurelid Floater
Source: Pet Battle. Most of Zereth Mortis' aurelids are content to swim, but some are born to fly! Aquatic type. I believe there are at least four places where this little guy can spawn based on the level 1 Aurelid Floater seen at each point.
The Aurelid Floater is a wild battle pet found in Zereth Mortis that spawns in water at multiple known locations but rarely appears in its capturable battle pet form.
Guide awaiting review
Travel to spawn locations
Head to the known spawn points in Zereth Mortis: at 57.62, 82.44 and at 51.95, 74.94. The Aurelid Floater always spawns in the water at these spots.
Identify the battle pet version
The Aurelid Floater commonly spawns as a non-battle pet, not a capturable version. If you find a non-battle pet Aurelid Floater at 57.62, 82.44 or 51.95, 74.94, do not kill it — instead, kill the battle pets in the surrounding area, and the non-battle pet version may be replaced by a capturable battle pet version after roughly 1 to 2 hours.
Capture without accidentally killing
When you find a battle pet version, use a Terrible Turnip and its Weakening Blow ability, which cannot reduce the Aurelid Floater below 1 health, so you avoid accidentally killing it during the capture attempt.
Try War Mode if unsuccessful
If you have cleared the spawn points at 57.62, 82.44 and 51.95, 74.94 for an extended period without finding a battle pet version, try enabling War Mode, as at least one player reported finding one immediately after doing so.
Tips
The Predatory Helicid battle pet also spawns near 57.62, 82.44, so you can farm both pets at the same time.
