When I had a spawning pair of managuense, there would usually be 3 or 4 individuals out of each spawn that would basically be this color.
I would cull them and used them as feeders, I found the pale color made them look like some kind of generic unrecognizable species, but to each their own.
If you use this one, and pair it up with a normal one, there should be a few, or maybe a larger number of pale ones from that spawn, and if you breed those pale ones together, an even larger number from subsequent generations, and so on, and so on. Could take a couple years, and you'll have a pale line. Just make sure you cull any deformed mutations.
I've got plenty of hungry fish if I need to use any deformed ones as feeders , there's a few with dark patches on them but two dominant ones in the pack nearly all gold , a pure gold breeding pair would be nice to have for me , I've still got my breeding pair of normal jags too so you never know they could end up producing a few in one of there batches if you've found a few I'm the past 
