One reader thinks the answer is yes, and gives ways we could spot them https://www.newscientist.com/article/2587906-are-anti-black-holes-possible-and-how-could-we-tell-if-we-were-looking-at-one/?utm_term=Autofeed&utm_campaign=echobox&utm_medium=social&utm_source=Twitter#Echobox=1789083432