My raphael catfish whats wrong

[Belinda777]

I noticed my 3 raphael catfish has gone red by their fins, I do not know why and if this is normal or not.
They are new in the tank, been 12 days now. I only use natural borehole water. Temp and ph within limits. No hardwater. All compatible fish community. This is my 173 ltr tank with a bio-sponge filter.

 

[Aiken Drum]

Please take a read through the "unhealthy fish" sticky and give as much detail as you are able.

https://www.aquariumadvice.com/forums/f17/before-posting-about-unhealthy-fish-read-this-32451.html