Swimming/Underwater creatures only swim around ground level
EDIT: This is tested on latest Nightly Build (2019-07-06, 64-bit)
(apologies if this is already known, I did try searching for it)
I am building a mod that adds fish, and was frustrated to find that I could not get them to swim above ground level unless they were in combat with me.
When I tested my mod in the vanilla engine, they swim above ground level just fine. Further, I've noticed that this applies the vanilla game underwater creatures - most noticeably Dreugh, which swim with their lower body submerged in the ground, only coming up when attacking the player. Slaughterfish do not appear to be as obviously affected.
Attached: 2 fish in the vanilla engine swimming at different heights, 2 fish (groups) all swimming on the ground in OpenMW.