Newly acquired African Dwarf Frog death

[akengle]

My 13 year old daughter started her 20 gallon freshwater aquarium 16 days ago. We treated & tested the water (ph & ammonia) for a week before adding any fish/frogs. She originally started with 4 guppies, 3 Mollys & 1 African dwarf frog. So far all of the above are doing well & seem healthy & happy. Two days ago we added a second African dwarf frog as company for the original. It passed today. It continuously stayed at the top of the tank, began shedding near its eyes & became pale. Everything checks out fine ammonia & ph wise still. What should we do to ensure our original group stays healthy outside of a water change? Should we replace the filter in case it had something that could spread? Any help is appreciated as we are new to tank life.

 

[Aiken Drum]

Please take a read through the "unhealthy fish" sticky and provide as much information as you are able.

https://www.aquariumadvice.com/forums/f17/before-posting-about-unhealthy-fish-read-this-32451.html

Please provide details. Saying ammonia and pH is fine isnt helpful as we no way of knowing what you consider fine. Nitrite and nitrate are also important to know.

On the face of it you are unlikely to be cycled. Running a tank for a week wont cycle the tank, and then getting the water checked won't tell you anything as it has never had anything living in there to produce waste. All you are testing is tap water.

So you need to cycle the tank.

What do understand about the nitrogen cycle and how to cycle the tank?