Route 12 has 6 wild species on its encounter table, appearing between level 9 and 14. Rates below are the chance of each species when an encounter triggers, not the chance of an encounter itself.
The wild Dokimon you can find here are Flounder, Loomleak, Toppa, Snowla, Gumba, Aoimon. The most common encounter is Flounder at 25%; the rarest is Aoimon at 8.3% — worth knowing before you settle in to hunt one specific spawn.
Water
Flying
Ice
Poison
Dark