Is this a decanter or a bottle?

It is a glass bottle shaped like a horse, meant to hold and display whiskey. It works as a decanter in the loose sense, but it has no stated aeration or filter features.

How much whiskey does it hold?

The listing does not state a capacity. Check the bottle's dimensions before buying if you plan to pour a full standard bottle into it.

Does it come with a stopper?

No closure is described. Assume you get the glass bottle itself unless the buy box lists a stopper or cap.

Can I put it in the dishwasher?

No. Handblown glass with a sculpted shape is best washed by hand in warm water to avoid chips and clouding.

Is it good as a gift?

Yes, if the person likes horses or unusual barware. It is a display piece first, so pair it with a bottle of whiskey rather than expecting it to improve the drink.