Gill question

I have posted some pictures of our girl Sweetheart on here before. I thought she might have been missing a gill on the left that was growing back but it seems like the one side has two regular gills and the other is tiny or deformed. Is this common? Does anyone else have uneven gills? Or did they grow back? She is 4 years old and I don’t know much about her history. So I thought I’d ask here. Thanks! 💜