Our pleco died a couple of weeks ago and the tank really was becoming algae ridden quickly, since sunlight hits the aquarium. Okay, so I bought the fish yesterday, plus 2 marbled mollies for my daughter. And, um, we can't find them today. There are the same 5 fish as ever in the tank. Oh wait, they came back -- never mind. I'm laughing at myself, because we literally spent 10 mins looking for them this morning, and now I glance over and can see the two mollies swimming by just as I was pondering their fate (did the others gang up and kill and eat them overnight? Did we imagine going to the fish store? What is the nature of reality and perception anyway?).
But never mind. They're there. Ha!