Help With Pangasius Catfish New Arrivals

[joel08]

Hi I bought these 2 new Pangasius 2-3inch catfish from my local fish shop. They looked healthy no signs of ill health. I  transported them back home which took about 5-6 hours since we live very far away. 

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The following evening I noticed whitespot disease and flashing on the gravel so I started a whitespot treatment the next day saying use half the recommended dose, I also raised the temperature to 29 degrees celcius (84F) to speed the lifecycle up and increased aeration. 6 days after there is still some signs of Whitespot disease and now the pangasius have a red tint of lines on the base of their fins on both pangasius. They are not like blood vessels or sores they are red marks only at the base of the fins not spread out throughout the body or fins. What could this mean?
 
I have done 2 water changes so far and checked the water params are safe.
Ammonia:0, Nitrite:0, Nitrate:5ppm, pH: 7.5. They are in a 55 gallon tank 4 foot tank and this is perfectly fine for their current size.
Can someone please help me I don't want to lose these new pangsius they are hard to obtain?

 

[Wills]

Hi Joel, what medicine are you using? For whitespot I usually use waterlife protozin which gives good results. You should be able to use that at full strength as well. As long as only a few spots survive you have a while it takes a lot of spots to kill them. So you can often take a few doses to get the parasites out of the tank.
 
Just wondered where abouts in the UK you are from? 5 - 6 hour drive is a very long way to be away from anywhere in the UK?
 
And the Pangasious are so hard to find now because there has been a lot of campaigning to ban them from being sold in shops due to their adult size.... while I sort of agree that 4 foot tank is ok while they are 2 - 3 inches but they are going to grow extremely large and are going to require a pond sized tank when adult.
 
Wills