Drop it in a three by three pen surrounded by doorframes that is slightly in the water. It's ai will make it move In circles very slowly around the edge because it switches between in and out of water. Every circle or three, depending on your settings, it will be hungry and it can usually be fed easily as it passes
For beginners these things will spot you in a split of a second so don’t even think of going up to it with a stimberry in your hot bar. Instead, get a ghille suit and sneak behind it and feed it a beer! Don’t use stimberries it is pain And time consuming unless you have a bush of stimberries. They eat berries after they are tamed though. Not beer.
To tame this creature you have to passively tame it, the best way of doing this is to put on a full set of ghillie as that supply's stealth, then you Aproach it from behind crouching and Feed it a beer!