When breeding otters throw Mum into a wooden cage, stand in there when she's ready to give birth and then it tends to make it easier to imprint on the baby. Saves you building a room for them unless of course you already have one spare
It is tamed in the same way as the Hesperornis, where you have to carry a dead fish to it. Larger fish, and those caught by Ichthyornis, apparently work better. Piranha are better than coelacanths for taming, and salmon are better than piranha.
Just push this cute lil creature in front of a giga and it'll have an existential crisis. Realising the path of destruction it left in its wake and deteriorate in front of the otters blue sparkly marble eyes