It looks like it could" be a type of Podocarpus.
I don't know where you are located, but at this time of year in the U.S., this poor little thing needs to be outside. Acclimated at first - as in shade for a couple of weeks & then gradually brought into full sun for a couple of hours each day, increasingly. There is not going to be any place in your house that is going to give it the light requirements it needs. It's obviously dying from too little light & too much water.
Until you can get a definitive i.d., it "MIGHT" have to come in at frost-time if it turns out to be some type of tropical, but chances are good that it's a permanent outdoor bonsai, meaning that with protection it will do best living outdoors - even at temps down to 20 degrees or so.
(Also - do some basic bonsai research as far as care & watering techniques. Will give you an edge on possibly saving this little tree.)
My body is a temple. Unfortunately, it's a fixer-upper.