Mystery of the Missing Fish

It's time for another installment of "The Vicious Lives of Fishes", featuring the guppies in my old glass malted milk jar.  The last time, I had changed the water and accidentally crushed one of the females with a slippery rock.  That left me with 5 guppies left, 1 male and 4 females.  Then I bought a pink and yellowish-green plastic plant, then a baby fish immediately appeared.  Actually, 2 baby fish appeared.  Then I saw a third one, but that vanished.  Then when I changed the water today, one of the females had gone.  I'm sure she didn't go down the drain, because I use a strainer, unless she got stuck to the plastic plant when I pulled it out.  Where did these fish go?  It's not like a baby fish because it's too big to allow itself to be cannibalized.  If it jumped out, I didn't see any fish carcasses in my bedroom.  Fish mysteriously disappear from my fish bowl.  Now I have 1 adult male guppy, 3 adult females, and 2 babies.  The male fish seems kind of tired after I changed the water.  Maybe it's time I need a new male fish.