Cycling new tank, added 1 guppy, died

Question
We (newbies) had setup a new 5 gallon tank on Friday, added AquaPlus to tap water and Cycle to the AquaClear 20 filter.  Waited till Monday and added 1 male common guppy.  He seemed okay, swimming, active, but didn't seem to eat.  Tested the water on Tuesday, pH 7.6, soft water, no ammonia, no nitrite, water temp 72 degrees (no heater).  Wednesday morning, noticed fish staying at water surface.  By evening, poor fish was dead at the bottom.  My 4-year-old cried.  Retested the water, same pH 7.6, no ammonia, no nitrite.  Help.  What did we do wrong?  What should we do next (other than a decent burial)?  Our goal is to have 3 or 4 male fancy guppies.

Answer
Hi CK;

That's a shame. I'm sorry this has been such a traumatic event for your little one. It might just have been the fish itself and had nothing to do with what you did or didn't do. Guppies are just not the hardy robust little fellas they used to be.

Try again but make a 25% water change first. Also be sure to acclimate him to the tank by floating the transport bag on the water for about ten minutes. Add a little of the tank water to the bag during the floating time. When it's time to release him onto the tank, net him from the bag to gently let him go into the tank and throw away the bag water.

You may know about it already but here is my page about new tanks to help you through the first few weeks;

http://www.xanga.com/Expert_Fish_Help

I hope it works out better next time...

At Your Service;
Chris Robbins