Ok, I was able to make the picture much larger on my work computer and I can say with 99% certainty that you have ich. The good news is that you have caught it early and ich is very treatable. It’s likely brought on by the stress of moving. I’m going to break the treatment steps down super simple since I don’t know how much you already know. I’d rather be extra detailed than accidentally leave something out.
The easiest way to treat your betta is going to be getting a small ‘hospital’ tank set up. Many pet stores sell small 1-2 gallon ‘starter kits’ with heaters and filters pretty cheaply. It’s not great for your betta long term but it makes treating an illness much easier and cheaper in the long run because you are only dosing a small amount of water.
You will need a tank and filter like this, an adjustable heater and thermometer, a bubble stone, air tubing, suction cups, and valves, and an air pump.
I’ve linked some items to give you an idea of things that will work, but you can absolutely do things differently. If you can’t set up a hospital tank, remove the snails and live plants from your tank, as the meds will kill them.
You will need to cut the filter pad and remind the carbon crystals. Use a razor to cut the bottom and one side of the back of the pad and shake out the carbon. Replace the filter pad and set up the tank as normal.
You want your temperature to be around 80-82 degrees F, as the higher temperature speeds up the life cycle of the ich, meaning you can treat it sooner. The ich cannot be killed while it is on the fish, so you have to wait for it to grow enough to fall off the fish and float in the water. Heat makes this happen much faster. (A week or two instead of months). Make sure you have a bubble stone in your tank when you have temperatures this high. Higher temperatures mean less oxygen in the water, so you need to aerate the water with the bubble stone to help your fish breathe.
Once the tank is set up and filled, treat the water with a dechlorinater. I like to use Amquel + and Novaqua+ to treat the water and help de stress the fish, but you can use whatever products you like.
To treat the ich you need 2 products. Kordon Methylene Blue and Kordon Rid Ich Plus. I have used these the entire time I’ve kept fish and they work very very well.
The rid ich plus is dosed 10 drops per gallon. You can dose every 6-12 hours. Change 25% of the water before every dose. Continue treatment until your fish has been symptom free for at least 3 days.
The methylene blue is used as a dip. It helps boost your fish’s blood oxygen, treats fungus and secondary bacterial infection, and is just a good secondary treatment for your fish.
I suggest mixing this up in an empty milk jug, as it can be stored for later use. Don’t store in a metal container and don’t store in anything you like, as it will stain bright blue.
You want to mix up a 50 ppm solution of methylene blue, so in one gallon of treated water, add 1 and 3/4 teaspoon (8.2 mls) of methylene blue and shake very well. If you want to mix up a smaller dose, you can mix 1 cup of water and 1/2 ml of methylene blue, but since you will be treating multiple times, it makes sense to make a bigger batch.
Once it’s mixed, catch your fish in a net, pour a small amount of solution into a small container, dip your netted fish into the solution for no more than 10 seconds (remove immediately if the fish seems distressed), then put the fish back in the tank and dispose of the used solution. Do this once per day until symptoms subside.
This will stain everything blue, so put down paper towels and don’t use any containers you like. It will also stain areas on your fish that have been damaged, so you can keep an eye on any spots where ich may have been.
Be careful not to share equipment between tanks as ich is highly contagious and can survive outside of water for short periods.
I wish you all the best treating your fish. Please feel free to send me a message if you have any questions!