Can someone please identify the gender of my fish. I think it’s a koi betta fish? But I’m also unsure if it’s male or female. If this additional information also helps indicate the gender- it was more expensive than the typical male looking ones.

I'm looking for a Betta that can just accompany me at my desk. I'm hoping to put a snail in their tank so I don't want them to be aggressive. Also, I'm ok with a betta that is not colorful. I was wondering if there is a species or gender of betta that would be better for me or if they have...