Water params are good, I have been feeding my motoro enough for 2 rays his size for about a month so that there would not be so much strain on the bioload. The only ray that came in thin is the guyana ray. I can see pelvic bones and a dent in his head. PH is 6.7 Nitrates are around 10 or 15 right now. No ammonia or nitirite. Temp is 82
Good news, the reticula and the histrix are happly chasing ghost shrimp around the tank and (although they dont like it as much) eating grocery store shrimp and squid. I will try live black worms for the guyana though.
None have a pink belly or any signs of anything abnormal on the tail.
I use small rounded black gravel for a substrate. My motoro hasnt had a problem with it and it has no sharp points or anything.