mandarin goby problem

Do I own a male or female Mandarin? I recently rehomed 2 mandarins and the one in the pictures below has been picked on a little by its male counterpart. They are about 1.5-2inches. I believe I have a female but I just wanted some assistance with this. Does anyone else have this experience of...

I have had a mandarin goby for six months that I trained to eat pellets and frozen foods right now it’s probably around an inch and it is female. I recently bought another mandarin online where I asked if they could send me a male but when I got it it turns out it may be a female since it too...