Edited-Betta Velvet Situation?

Edit-I'm so sorry for posting this twice, but the app was a little confusing and it didn't let me put tags and I'd really like for more people to see my thread, I also don't think I have enough info. I'm so sorry, I'm new and concerned

Please help! I got my male betta about 2 months ago, when I bought him I noticed slight fin rot, so I gave him the 10 day aquarium salt treatment. I saw some regrowth, so I put him in his 5gal planted aquarium. I noticed the type of tank I had was too tall and the led lights that came with it did nothing for the plants, so I invested in a 10gal planted tank with fluorescent lights. I sped up the cycling for it with some biomedia from the 5gal, and I got the water tested at Petsmar, I don't remember the results exactly, but they said it was fine to add some fish into. So I have 3 Cory catfish and 3 Sunkist shrimp in there currently, and I was intending to introduce my betta into that tank eventually as well since the 5gal narrow vertical tank was a terrible choice for him to begin with. However, I was looking at him today and noticed his face was discolored, and when the light shines on it, it flashes a bronze-gold color. I never noticed because he's bright red with natural gold flecks running horizontally along him. It doesn't exactly resemble the pictures of velvet in seeing online, but it's definitely crusty looking. So I now believe I'm stuck with the infected 5gal that has a built in filter that I imagine is quite hard to cure of any velvet inhabitants, and my 10gal tank with healthy Corys and shrimp that I hoped my betta was destined for. I know this is terrible but I have him in a 1/2 gal bowl right now because I don't know what to do with him. I don't have the funds to buy another setup, the only things I could buy right now is medicine if I can find any at my local pet stores. He eats just fine and his fins aren't stuck to his sides at all. I would love to get some help/suggestions asap on what to do on a tight budget, because I care for him and my other aquatic critters dearly. So I really don't know what to do. Is it possible for me to kind of "disinfect" the 5gal even though it has the built in filtration system? I believe it's a Marineland 5gal Contour tank or something to that effect.

Side Note: I believe he had velvet when I got him, I noticed just the slightest discoloration on his face and I tried googling it, and I literally found a forum that said "some just have crusty complexions" and I was dumb enough to to believe it. I feel like a terrible fishy owner So I've joined this forum because I've found it to always be very helpful in all my newbie questions

These are the only good pictures I could get of his face.

 

The discoloring is probably from stress.I'm a little confused are the cories and shrimp in the 5 or the 10,if their in the 5 your way overstocked.I f their in the 10 be careful cories and a Betta is a little over stocked.but since the betta is in the 1\2 gallon,just dump out the 5 gallon and let it dry in the sun for a few weeks and get rid of all filter media.then disenfect the tank with soap,then clean out the soap.treat the betta with meds.

 

So he will be fine in the 1/2 gal for a few weeks? I'm just a little concerned because it doesn't have a filter or heater or anything, but I've been doing daily water changes adding just a tiny bit of aquarium salt to it. My cories and shrimp are in the 10gal, heavily planted with lots of hiding/chill spots. Thank you so much for the help so just generic fish medication should help him? Like a destresser?

 

I will get back to you once I do some research,but yes he is fine in1\2 for now.what type of Corrie's do you have?

 

I have 3 little panda cories.

 

I have 3 little panda cories.

My understanding is that Cories do best in groups of 6 plus. I would also be concerned about aggression toward the cories from the Beta. Moreover the cories and Beta are not temperature compatible. The betta needs higher temps. Also, the Beta may see the shrimp as a snack. Personally, I would put the shrimp in the 5 gallon that you have and rehome or return if possible the Cories. I would then move the Beta to the 10 gallon by himself. When I moved my Beta from his 0.5 gal to the 10 gallon there was instant improvement of his health in all respects.