So confused..please advise (possible cotton wool disease/white spot..?)

Hiya, would appreciate some advice please
I noticed one if my male bettas was unwell this evening- not eating, pale and upon looking closer I could see the edges of his tail and fins looked odd (like sluffy- if that is even a word.. hard to spot almost as he is light in colour but definitely weren't right) so I started looking up what it might be - no other noticeable symptoms.. other than not moving around much.. only simerlar symptoms I found was external columnaris (mucousy looking membrane on tail) yet none of the other symptoms - not rubbing on objects to scratch, no discolouration of gills, no ulcers or lesions however I did read there two strains slower and faster (the latter taking hold and killing fish within 24hours before showing symptoms), his water quality is good (as are all my tanks as I use the water so check and maintain routinely) yet 24hours previously i had put him into a tub with a female to breed being careful regarding water temps reamining same etc however not long after introducing female who initially showed interest she became so hostile with him that i decided to remove him and return him to his tank so could have suffered some stress as a result.. i also read some conflicting info online saying external columnaris infection is also known as cotton wool disease cotton fin fungus) and some articles saying they are not the same i went back to him this eve and lowered his tank temp slightly, added some extra plants and an airstone and I tried to get better a better look at him at this point cus he was hiding and I could see ever so slight fluffyish cotton wool like substance had begun to develop on one of his sides but cannot see anything else (one article stated that if there is and fuzz to the white discolouration then it is definitely not external columnaris so i assumed it could be cotton wool disease..) ..my main concern now is to try to determine if it was most likey to be this? And assuming it was wat measures i need to take to prevent the spread and my others (all bettas) from contracting this -as articles state its highly contagious (particularly those with lowered immune systems)...I have some new tanks i had started to cycle with no fish in atm that I had seeded with some of his gravel, plus some micro worms and insuforia collections which I top up with water from existing tanks wen needed (which may have had his tank water added but not certain..), my main questions are wat is safe to use to disinfect the empty tanks and content - gravel, filter sponge etc (assuming I have to start over) or do I just treat the water? I read that both conditions are highly contagious that the bacteria/fungai already exists already in our tanks and only takes hold n affects those with with a weekend immune system if that is the case then surely other fish who are healthy are not at risk or is it the fact that once it is present it is then a sanger to all fish??i also read that if its pretty it will like always be there.. so wat does the mean that it doesn't die off on its own ? I'm finding it hard to know wat to do for the best..Exactly how dangerous is it to my other fish? - I read in articles that other fish should be treated regardless however advice from admin on a betta support group on face book stated i should not treat fish if no symptoms are present, stated they could not confirm if it was in fact ikely to be cotton wool disease without having seen the fish with his symptoms and advised to just do water changes every other day and disinfect equipment.. would it hurt to treat them for it regardless? I have one group of femles in one tank, 5 week old fry in another tank, a few boys on their own in tanks who have not had contact with him, a female he was put to breed with which I then returned to my main tank with rest of females bit now she is currently in a tub on her own -as I am unsure if she could be infected and if so possibly infected my main tank and rest of my girls..?? If she was would she inevitably show symptoms over a certain time frame? If she doesn't does that mean she is fine ir could she still be carrying it without showing symptoms or becoming sick.?? Because I don't know i am afraid to put her in with others for obvious reasons until I'm certain- how long do I need to wait to be certain and maybe it doesn't matter anyway cus she did go back in there briefly??wat do i do with her, right now she is in a large tub (which she cannot stay) but i dont want to put her into the newer tanks that were seeded with his gravel which test strips say water is good but could it still be contaminated? If that the case then if she is OK and I put her into an infected tank or vice versa..is there any way of knowing if its presant in ur tank? And really what is the point in starting the tanks all over with fresh water to house already infected fish? doesn't make sense to me cus then the water is then uncylced and if they already infected surely it makes no difference to them then and u treat them in the tanks.. if u treat a fish with symptoms does it also treat the water/filter/sponge? If that is the case and no way of knowing in my opinion it best to treat all regardless before they become sick.. just to be safe? And wat to use? Even read that tee tree oil can be used?? (See attachments).. also, If I do get more fish with symptoms and it is better to treat all-do I also treat the fry tank? If I shouldn't treat fish without symptoms and advised against it can I treat the tanks that don't have fish in yet rather than disinfecting and then recycling as u would not do that with a rank full of infected fish (or do u?) TbhI need the additional tanks now if I do need to remove individual fish and quarantine since my spares have now possibly been contaminated with the use of same equipment/water.. thinking of my main tank with females in- is it possible the water be infected but not the fish.. if so is it an option to remove the fish without symptoms and treat the water?? Plus should i not use the microworms and insuforia now for my fry if it could be contaminated..yet they live of rotting veg as it is how long could it live in those conditions before it dies off and is safe to use again.. ?) Sorry for so many random questions and rambling on but Im finding it all very confussung tbh not sure if it cus i am overthinking it all and complicating it more for myself.. but feel this is because of the lack of knowledge n experience with this on this on my part and the vast amount of info online and varied opinions does not help me feel certain wat to do.. also please advise wat best to use to sterilise equipment that has been shared between tanks..mainly the tube i use to remove uneaten food at bottom of tanks as this has been used once in his tank...I use it frequently in fry tank but afraid to now until I sterilise it but don't know wat is safe to use (I normally use white viniger and boling water and salt for general cleaning and only chemical products i have here is beaphar deep clean spray suitable for all reptile and amphibian housing) is this productsafe to use and strong enough to sterilise?? The admin on Facebook group advised soak in bleach 1 part bleach to 19 parts water..for 10=15 mins ? And then in prima and water but I don't use bleach or have any here i can use here - I can buy tomorrow but would like to do ASAP tbh.. I read on one article said u cun soak items in 3% hydrogen peroxide - I have got a bottle of 12% liquid peroxide used for colouring hair which i could water down - is this the same as bleach? Can I use this for equipment including for fry) if so how long to soak and rinse beforw using etc... if wat i have got here no good please advise wat i need to buy to proceed..
Also wat about the filter n sponge used in the tank that my fish died - bleach? Throw away? And same for the plants also - throw them away?
my biggest concern honestly is the fry due to their size, lack of available information plus the food and equipment are not easily available for an instant replacement...
Sorry for such a long post that goes on and on.. but its only because I don't want any more losses.. im greatful for anyone with some knowledge or experience regarding this for some advice n on this please -especially concerning fry and how susceptible they might be..thank u

Update: I now have another fish with symptoms...(see pics) can anyone please advise for me to buy the correct treatment..

I'm not reading any of that because there are no paragraphs or gaps between paragraphs.

Sum up the issue in a couple of sentences and post a clear picture of the fish from the side.

Yeah please summarize

I actually did try to read it, but it's not easy and it's hard to focus. You're asking a lot of not always related questions, I suggest you split it into separate posts and place them accordingly on the forum.

Some of your questions are about the equipment, cleaning and hygiene. I'm sure that can be thrown into a separate posts, as a lot of us will have a better experience with that stuff VS an illness that some of us did not experience

You're asking about various tanks / fish AND fry, tanks, water.... Try to bulletpoint your questions, we can use 'quote' option to reply to them and avoid confusion

I will answer two questions now:

Daft punk said:

is it an option to remove the fish without symptoms and treat the water

Click to expand...

Treating water involves adding things that are not always good for the fish. If you're having an outbreak of any illness or if you're unsure you're better off doing a water change. Whatever bad thing is in your tank will get greatly diluted and in a few days removed. I ain't no expert but I wouldn't be so sure about the 'fish with no symptoms', if you already have more than one ill fish then it's a matter of time.

Daft punk said:

And really what is the point in starting the tanks all over with fresh water to house already infected fish?

Click to expand...

To dilute the bad water without shocking the fish, don't start from scratch - do a 70-80% water change If you follow the rules of changing the water your fish will be okay and the fresh water should help