Fish Swimming Up and Down Tank Glass

Question
I have two tetras and a cremescicle. I cleaned their tank yesterday and all day today they have been swimming up and down the glass. What is the reason for this?

Answer
Sarah,
They could be seeing their refection in the glass, or they could be having problems with the water. When you say you cleaned the tank, did you remove the fish and then dump the tank and add new water? If that is what you did, did you use a water conditioner with the new water? Did you make sure the new water was the same temperature as the water they were in? Once I get the answers to my question, I can help you better.