Yellow ram and guppy, fin rot? HELP

So I have a 38G tank with
3 pearl danios
4 Cory’s
1 blue gourami
4 platies
And previously 1 male guppy
Perimeters
Temp: 76 F
PH 7.6-7.8
Nitrates 20
Nitrite 0
Hardness 15
Alkalinitybetween 120-180
Ammonia.25
*these are my typical reading. The nitrate and ammonia are the same as from the tap (I have well water w/ no chemical filter)
2 HOB filters
-Penguin biowheel 200 (marine land)
-fuval aquaclear 70
* put in about 2 weeks ago planning on swapping the penguin for aqua clear

So about a month ago I woke up and noticed that my male guppy had last 60% of his color all over his whole body. I checked the water levels and they where as they are above. Surprisingly none of the other fish ever messed with him, he had his own corner of the tank and even the danios and gourami respected that. Then with in the next 2 weeks his tail started to shred and look super rough on the edges. I assumed it was fin rot and moved him to his 5 gallon rival spec hospital tank with air stone and heater. I treated him with Malfix and nothing. He has still not shown any improvement or decline. He has no white on the tips or red makes threw the tail or even swelling at the base of the tail.
Now I have a little yellow ram in my 38g tank that has a hole in his dorsal fin that’s about the size of half a pea now that started out the size of a pin head when I first saw it. It has fuzzy white edges and I can see the “Ray” part ( that runs between the soft tissue on fin) that is still in tact but everything else is gone. I treated the whole 38gal tank with jungle fungus clear tabs and over the past 4 days there was no improvement and almost looks like it’s getting worse.
I’m at a loss as of what to do, I love my fish and don’t want them to suffer. Can anyone give me advise?! Please I don’t want my fish to die.

Finrot is the direct result of poor water conditions, how often do you change water and how much?

You should be doing at least 75% once a week.

Is the tank cycled?

Can you provide a couple more pictures of the male guppy, and one of the gourami?
How big is the gourami?

Fungus appears as white fluffy stuff on the fish. The ram does not have a fungal infection.

Bacterial infections usually show red from blood and the ram has no red around the dorsal fin so it is unlikely to be bacterial.

Protozoan infections can show red when they get really advanced, but usually do not show any red unless it is really bad and chewing into the fish's body.

The ram does not have a really bad infection and there is no red (from blood) around the damaged area, so I would say protozoan and I reckon the guppy has one too. But the guppy's tail looks like someone has been taking bites out of it.

How long has the tank been set up for?
How often do you change the water and how much do you change?
How often do you gravel clean the tank?
How often do you clean the filter and how do you clean the filter?
How often do you feed them and what do you feed them?

Yeah I’m kind of stumped and I also thought it looked like someone had been biting on him but he has been in his 5 g tank now for 3 weeks and hasn’t been getting any better. Still dull color and tail almost looks like it’s getting shorted. The gourami doesn’t have any issues, at least I hope not! But I will get some more pictures of them and post in the AM.
I do water changes 2-3 times a week, 10g every water change and I vacuum the gravel every time I do a water change. (Alternating on which side I do therow as far as move everything to one side, and move it back then vacuum around the decorations on the opposite side)
I clean the filter one a month and take wipe out the inside and get rid of the build up inside the filter.
They get fed twice a day. A small pinch of National Geographic tropical fish flakes and a small pinch of blood worms. And I was doing 3 pellets of API shrimp pellets or 3 algae wafers once a day for the cories but switched that to 1 1/2 wafers split into 4ths or 2 shrimp pellets split in half because I noticed I’d suck a few up when I would vacuum because they weren’t getting eaten.
The tank has been set up for 7 1/2 almost 8 months
And as far as I can tell the tank is cycled.
I did recently as of about 1.5 weeks ago notice a spike in brown algae growing on the glass which was weird. I don’t know if that has anything to do with it or not. I just chalked it up to the fact that it was about a day or 2 after the weather here got sunny and warm (I live in WA so it was very noticeable since it rained for 3 weeks straight and went from around 45 up to 65ish)
I think I got all the questions answered
What should I do if it protazoan, what should I do? The rams white hole thing is starting to reach down onto his back and I want to do what I can before it’s to late for him and my little Inego (the guppy)

THANK YOU FOR YOUR HELP!!!! I am seriously on the verge of panic and haven’t been able to hardly sleep trying to figure this out!

The main reason I wanted a pic of the gourami was to see if it is a big male gourami, they can sometimes get nippy and bite the other fish,

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I would do a 75% water change once a week rather than 25% three times a week. The bigger water change is more effective at removing unwanted pathogens in the water. Just make sure any new water is free of chlorine/ chloramine before it goes into the tank.

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If you get a broad spectrum medication containing Methylene Blue and Malachite Green, it should treat any protozoan, bacterial and fungal infections. If the medication does have Methylene blue then it will probably wipe out the filter bacteria so it is preferable to treat the fish in a separate tank or take part of the filter media and keep it in another container without medication.

"Waterlife Protozin" should do the job but there are plenty of other similar products.