Trying To Get New Tank Started W/ Fish Refusing To Eat

Several weeks ago my 6 year old son picked out two platies to put in a 2.5 gallon tank. We brought them home and set everything up. The first couple weeks everything was fine, fish were eating, active, etc. At some point I noticed one fish was being a bully so I started doing research. I learned that the tank was too small. We upgraded to a 10 gallon tank and the the weaker fish died after the transfer. Its been about a week now with the new tank and only one platy in it. Ever since the transfer the remaining fish will not eat. Initially he was hiding and not being active. He now swims throughout the new tank and acts & looks normal but still will not eat. I tested the water yesterday and these are my results.
Ph 8.0 (which is the same reading as my tap water)
Amonia .25
Nitrate 0
Nitrite 0
Temperature is 80 F
I understand that my tank has not yet cycled. I am doing 10% water changes daily and adding prime and checking my water every other day.

These are my questions:
What do I do with a fish that wont eat? I assume he's going to die. If this fish dies is it safe to add another fish or two to my tank? Should I be concerned about a possible disease lingering in the tank that will continue to infect any new fish I add? Or should I just assume that the fish is suffering from new tank syndrome? And lastly the gal at the LFS suggested that I add a couple more fish now. She says that the platy may be stressed because he is alone. I am obviously concerned about introducing new fish when the tank is not cycled. I don't want to keep killing fish. Advice?

What test kit are you using? What have you tried to feed to the remaining platy? Do you have a picture of him/her?
 
When a fish isn't eating usually I would look at water quality or possibly internal parasites..but with how new the fish is and being moved to the newer tank so quickly after being in the other, he may just still be settling in.
 
Adult fish are usually fine to go up to 2 weeks without feeding, and usually will not refuse food so long as to starve to death.
You may try soaking his food in garlic to make it smell better (and boost his immune system), or trying some other food..like frozen bloodworms. These are usually happily eaten.
 
In your case, though..I know you don't want to hear it. I would return the platy to the pet store.
It's great that you got a bigger tank for him, but they still require a minimum of 15g. It's also best to not put it through a fish-in cycle, if you can avoid it.
 
Do not add any more fish right now. Platies are not schooling like tetras though I think they do appreciate some company, but adding more fish will just make the water quality worse.
 
If you return him like advised, then I would hold off on getting more fish and do a fish-less cycle following THIS.
You'll also need a liquid test kit (you may have that already?) and some ammonia which you can find at Ace Hardware.
 
If you do want to continue keeping him have a read of THIS and THIS for fish-in cycling.
Do you know anyone with a set up tank that could give you some of their filter media? Whereabouts are you, if I may ask?
 
I hope I havn't come off as too negative and that you and the platy can get through this.
Please don't beat yourself up by the way, a lot of us start out like this with misinformation from the LFS.

Thank you. I have read that mollies and platies are ok in 10gallons. Is that not true? What type of fish do you suggest? This was my son's birthday gift and he is being really patient while I get everything going. I just wanted him to have two or three happy and easy to care for fish. Im using the api master test kit. I don't know anyone who keeps fish. We live in southern California. Im trying to get a picture. Give me a minute

You're welcome, unfortunately that's not true. Platies need a 15g and mollies need a 30g.
 
That's great your son is being patient, I think both of you will be happy with the fish once you can get it all figured out!
 
In this size tank I'd be doing some micro fish like mosquito rasbora or green neon rasbora (these both require groups of 6 or more), or a couple pairs of peacock gudgeons, or a single betta.
*Edit* Although, now that I think about it, the rasboras may not be a good choice as I think they like softer water. Do you know if your water is hard or soft?
 
A site I like to use for information on fish is seriouslyfish, if you want to look around on there. Of course always feel free to ask about the fish here too
 
I'm in Georgia so sadly can't offer any filter media. To upload the picture (if you have trouble) you can go to 'More Reply Options' at the bottom of the page and attaching files.
If this doesn't work you can upload the pics to a photo sharing website like photobucket and then link them here.

Im just guessing but I think our water is hard. Btw I am feeding flakes right now which he was more than happy to eat prior to the tank switch. What about my concern about a disease lingering in the tank? Is this something that I should be concerned about? Still working on a picture. He's not cooperative.

these are the best pics I could get at the moment. I know we need more hiding places. I am still working on the decorating.

The other platy could have died from being picked on, being in an uncycled tank, or illness. There isn't really a way of knowing. As far as your remaining platy, if he seems alright besides not eating, unless he refuses blood worms or garlic soaked food for over a week and begins to look malnourished or act differently, I wouldn't believe he is sick, so I wouldn't worry about lingering disease.  Since the tank is uncycled and it is a small tank, I would suggest upping the water changes to about 20 percent daily. That's only 2 gallons, you can buy a 2 gallon bucket for just a few bucks. That may make him feel better enough to eat. As ninj said, I would hold off on adding any more fish, and when you do, only add a few at a time, unless you opt to rehome the platy and do a fishless cycle. When you do a fishless cycle you can add your full stocking at the end. But when you do a fish in cycle, the tank is only producing enough bacteria to cope with one fish's output of ammonia
 
I realize this is your sons tank so it may not be an option, but the best way to have a healthy easy to care for tank is to do a fishless cycle. You can weigh out the pros and cons of returning this fish and having to wait a few weeks versus explaining why the fish keep dying
 
Kudos to you for doing research and trying to do what is best for the fish 

I'm with what Ninjouzata and squidneh have posted.  And from the photo I see nothing wrong with the platy.  Fish eating can be a bit difficult to notice...he may be eating and you just don't see it.  Platy like many fish will also go around picking at surfaces, eating microscopic food (some of it live).  I have a lot of characins, and the smaller ones in particular are fond of taking in a flake or pellet, and a few seconds later seem to spit it out.  But they have actually bitten off a very tiny piece.  After a few more, they may leave the last bit; but have got what they need.
 
Byron.

What about my PH being at 8? Is that a concern? I read about using driftwood to lower it naturally. Any advice or tips on that?

Platys actually prefer a higher pH, so no worries there. They appreciate hard water too. You said you think you have hard water. Do you have any like scale build up in the bathroom around your faucets? That's an easy way to tell. If not, your water provider website may have the information available to you.
He may be stressed because of a lack of decor, which sounds kind of silly but really is not. While typically outgoing fish, this species does appreciate floating vegetation, caves, tunnels, branches, or tall plants.

Thanks and yes we do have hard water that builds up in the bathroom. I am planning on getting the tank fixed up better. The good news is I think we are turning a corner with his health. He was even more active today and he actually took one bite of food. It was the first time in a week that I saw him go after the food. I'm going to try to pick up some bloodworms tomorrow. Do they need to be frozen? Or can I do the freeze dried?

Freeze dried foods can be problematic as they can lead to bloat. A pack of frozen bloodworms will run you about six dollars and last a long time with just a single fish. They are easy to prepare, just defrost them a bit by removing a little tank water and adding the bloodworms to this water. I use plastic medicine cups (one for each tank, as each tank needs different amounts of particular foods). One or two bloodworms would be plenty for a meal. Then you can pour the water with the food into the tank in front of the fish again, but only do this if you haven't prepared too much. 
 
Platys are pigs. They'll usually eat whatever you've got to give them. They appreciate a bit of veggie every now and then which is good for the digestive health, and some meatier foods, like the blood worm, but they also do well on flake or live foods (microworms are a bit small for the platy I just gave away, but she'd still eat them). Most of the vegetables you prep in your kitchen are good for your fish, too. In fact, if you buy jars of garlic in juice, you can use some of the juice with your fish foods as a tasty and healthy additive, as has been mentioned before.

I agree on the hardness, pH and feeding issues.  Feed minimally rather than too much, always.  And looking back at the temperature, I would lower it a bit from 80F down to around 77F.  The higher the temperature the harder fish have to work physiologically and this takes more energy away from other areas where it is needed, and it can wear them out faster.  77F is about mid-range for platy.
 
Byron.

Just wanted to update that my little platy is doing awesome! I gave him some broccoli after it was suggested last week and that seemed to kick start his appetite. He is back to eating normally and he looks happy. Also I think my tank is starting to cycle as I got my first 0 ammonia reading today. My Nitrites are between 0 and .25 and Nitrates are 0. Up until now I have been doing 10-15% water changes almost daily and adding prime. Should I hold off on the water changes / prime now that its starting to cycle?