I hope this doesn't sound rude or harsh, but Sam does not think it's funny to scare your Guppies. He is exhibiting normal curiousity.
The biggest roadblock to understanding critter behavior is to anthropomorphize. I see it a lot on this forum and had to deal with it on a daily basis before I retired as a canine behaviorist/trainer. To be fair to our pets we have to accept of their reactions and behaviors for what they are and not how we perceive them in human terms. Sorry, my soapbox.
Do you have a lot of plants as has been often suggested? Can you post a photo of the whole tank?
Turn the lights off in the aquarium and let the Guppies settle down. Wait two or three hours before you turn it back on.
When adding new fish always float the bag in the tank with the lights off and leave them off a couple of hours.
Thank you sooo much for your reply. So far I have the gups in the quarantine tank. Keeping them in there for a week. I can get a photo of a tank that looks almost indentical to it, but not the actual one. Camera problems, phone problems, technology hates me.
So Sam is probably just checking them out? He would go up to them and flare. One female got to close and he nips, but that seems pretty normal. After he would check them out he would go to the bottom and not move. The gups were terrified of him. Poor little fishes. LOl.
So...I will get the pics of the tank that looks like mine. I have been getting more and more plants, so its getting pretty heavily planted. I wish I could have real ones, but I’m a plant killer.:-?