Many fish will adjust and be OK. If he starts showing signs of stress (bad coloring) you may need to get him a tank with different parameters. Seeing he is young and you are not going to breed him you should be ok. I only say this because these are predominantly black water fish in the wild, just something to keep an eye on and be aware of. If his colors fail to come out real good or fade you might lower the pH to the low side of the SA parameters as this can be a sign of stress. Also note that black water is VERY low in nutrients compared to white water so your ammonia needs to be zero, nitrite needs to be zero, and nitrate will need to be super low as well. These fish thrive in water that is low in calcium and inorganic carbon but high in Organic carbon, Iron, Aluminum, and manganese.
You are correct!!!!!!!!! That is a HUGE score!!!!! Congrats Sir!!!! I gave up on finding one years ago.