Upgrading neglected 10 gallon to new 20/39 gallon

[pvcrisp]

Upgrading neglected 10 gallon to new 20/29 gallon

Two weeks ago, I took over a neglected 10 gallon tank. The lone fish in the tank had been living in stagnant water with no light and almost no feedings for at least 3 months, maybe longer. The first week, I got the filter running, did two 25% water changes, and got the light working. This week I did two 50% water changes.

I wasn't sure what type of fish it was and was worried about the red color in his gills, but looking at the pet store, I found more fish like him with the same red gills. Looking online I found he is a twin barred play and is swimming around pretty actively. (Stock photo attached)

After the first water change, the chemical levels were 8.1 pH and Ammonia/Nitrite/Nitrate were all 0. That didn't seem right to me, and I found out I needed to really shake the Nitrate test because it settles, after shaking as much as I could, I tested again and got the same result.

Today when I tested, I got an Ammonia reading of 0.5 and Nitrite/Nitrate of 0 still. I have the API Master kit and the lot numbers on the bottles range from 610-910, do you think they are no longer good?

I am in the process of looking for a used 20 or 29 gallon tank, I almost scored a 26 gallon bowfront, but it turned out to only be 16 gallons. Is a 29 gallon that much more recommended over a 20? I will be buying a new AquaClear 50 filter.

My primary questions, besides the health of my one fish are:
1) Is the tank going through the cycling process now that the fish is being fed and the water is being filtered?
2) If the tank is not cycling and is stable, I would love to just transfer to the larger tank, filter and all, how can I make sure the fish or tank does not have any diseases?
3) Should I just start the new tank out fresh with a fishless cycle and move this fish over when cycle is complete?
4) If decorations come with my new tank, what is the best way to clean/sanitize them?
5) In general, what would you do in this situation!

I know this in a lot in one post, so thank you for all the help!

 

[brennae]

I use very hot water to sanitize and sometimes bleach and sometimes vinegar. Use a good dose of prime with the bleach method (to rinse). Yes I would clean everything in a used tank. A platy could live in a 20g in my opinion but it depends on if you want more fish to go with it.

Good for you for saving this fish. One fish may seem insignificant but to that one fish it is a big deal!

 

[Jak]

I can answer a couple of those.

4. Vinigar. 10% white vinigar 90% tap water. Soak over night rinse rinse rinse. Rinse again chances are its clean. Use hot water if possible. And of course no soap.

5. If hes doing ok and looks healthy id say transfer him on to the bigger tank with the same filtermedia (or at least some of it) and treated water. Do a good cleaning and rinsing of the substrate/and decorations transfer them over to the new tank. Then cycle and start slowly adding fish.