Is this normal? Red T Shark, Rainbow Shark.

[Dakkon]

I recently added a red tail shark to my tank, and i already had 2 rainbow sharks. Within the past week one of the rainbow sharks now hangs out with the red tail, ever since, now his dorsal fin is dark red, dark enough that its basically black. Is this normal for my rainbow to try and match the look of my redtail shark? Is it possible these 2 can mate?


-Thanks!

 

[Dakkon]

this is my first experience with these species, so im not excatly sure, any info would help, thanks

 

[Wet Whiskers]

You might find a few more people with experience with these guys on aquariacentral.com. But, here is an article on keeping these guys together:
http://www.fishlore.com/Profiles-RedTailShark.htm