From looking at your setup and what you've said so far, i would lean more towards ammonia burn. The only way to know for sure is by doing a water test to check for the ammonia level.  While you are waiting to get a test kit, i suggest you reduce their feeding to at most one time per day and do a 10-15 %   water change daily.  Once you know the exact water parameters with the api test kit, you can adjust the feeding and water change schedule to make sure the levels stay in the safe zone.

Ellirianna, take a water sample (about half a glass full is plenty - just in case they need to repeat a test ) to the pet shop to test it and watch how they are doing it and how they read it. They should do it in your presence, while you're watching. Those tests should be free of charge. Please do it ASAP. This is very important

I tend to say ammonia burn too.
Also very important now, that you do those waterchanges daily.

I like your new set up very much. Maybe later on you can add a few more Elodea or Hornworth.

API Master Test Kit is very good, this is what I am using too.

I actually got this test kit (Link is not visible to guests. Please register to view.) It has good reviews and if you read them it does have a nitrate test and is just like the API test kit but cheaper only 20 with shipping. And I will go to the pet store to have a water test. But how is knowing going to help? I mean i'm already doing all I can for everything.

I didnt get to the pet store today my ride is not very dependable.

and i am doing every other day water changes. And thank you

I am going to try to go today and maybe also get some ammonia neutralizer they have ammonia burns and i'm not sure if they are healing or what but if the test comes back with high ammonia ( as it probably will) Then I will get it.

Your tank is getting there, keep doing those waterchanges.
Ammonia and Nitrite should show 0 and Nitrate no more than 40, less is better.
You'll make it girl

Oh crap, I forgot to warn you (or anyone) about the carbon filters since I'm not using any myself Well, just take the carbon pads out and dose again

The bettas sound so beautiful I was thinking about getting one to my 8 gallon. And placing some other small fish with him Didn't quite decide which ones yet... there was a beautiful cream-purple one and a glowing red one in the pet shop lately

LOL thats terrible. My fish refuse to eat the plants lol. And looks like i may be getting that lovely male very soon I think I found a person with a nice pond for them

The guy told me my goldfish are not worth it and flush them So I am not getting my betta soon but I am also NOT taking his advice. Yes I want a betta and it suits me better but not if I have to do something that horrible to my babies

well I called him because he said he had a few ponds he could keep them in. And I know I can take care of them. I also just found out that I can get a two gallon for my dorm and put my betta in it * squeals *

Of course I have to take care of things first like school and family and buying things for the present my friends are getting me ( I cant say what it is cuz its expensive and everyone keeps scolding me for liking it so much ( its nothing bad though)

LOL I dont feel bed about getting her she is lovely ... ( though I'm a tomboy so its surprising i like her lol ) its everyone else that has a problem with it.

The goldfish are doing well super active but I had to take out my guppies since the goldies were tormenting them. They are now in my half gallon bowl for some reason they only reached less than a half inch each so they are fine doing water changes and they produce very little waist

Hi Elli, I posted for you in "general discussion"

I read in a previous thread that you were considering giving your goldfish back to the shop. So in that case, maybe you should leave your betta tank waiting until things have sorted out with your goldfish? It could be too much work for you to keep an eye on two cycling tanks at once...

Glad to hear the fish are doing well

By the way, it's not that terrible to have two fish in a 10 gallon, I think the main problem for you happens to be that you didn't know about the nitrogen cycle so your fish kinda overwhelmed the filter system It should be fine once it'll be cycled

Elli you doing extra well.
But I know what you mean, I went through the same experience. I didn't know anything about cycling, etc.... only get a tank with some gravel, plants, water, filtersystem which comes with the tank and put the fish in, feed them a couple of times per day.... until I found this little forum here and THANKS to Nossie, Mindemae, Kat, Andrea, Katie I learned a lot and stil learning

Like lately I learned that the beneficial bacteria are not all over the place in a tank but mainly in the filter substrate.

Now, how to do a fishless cycle or at least start fishless: get some of your filtersubstrate of your already established tank into the new filter for the new tank. Set the tank up, put some fishfood in it and beneficial bacteria according to instructions on the bottle how much you need to start up a new tank. You may need to repeat this for a few times.

I did use "Stability" from Seachem lately. It sais it avoids the "new tank syndrome". Test the water regularly, including pH as bettas like the more acidic water than goldfish. Your tank will be cycled when ammonia and nitrite are 0 and nitrate is showing. This one should't exceed 40 ppm.

It is exciting setting up a new tank , please post pics soon, cannot wait