I have what I consider to be a docile male betta and I was wondering if he could possibly get a tank mate?

He is a male betta that I consider to be docile since I have never seen him flare or react to anything in a hostile way, so I was wondering if it would be possible to try and put a plain small feeder guppy in with him. The guppy does not have a large flowy tail and does not have any flashy colors- it is just drab grey and small. Is it ok to try?