Adam,
You are making me want to add either a pair of Thorichthys or Crytpoheros to my 125g. So what are you deciding to go with?
Hi ahud,
My personal opinion is that 2 Thorichthys is not ideal. They like to shoal, not a schooling fish per se but very social. Check out some of Darren's threads where he shows his Thorichthys spawning inches apart from each other.
My current state of mind is I will swap the gravel and keep all the fish, but I will reduce my mixteco numbers down to 9 or 10. The 4 or 5 mixtecos I move will be going to

I'm also going to be adding a school of livebearers, species TBD. I'll post more about that later, would like some input.