Well first off you make sure your tank is running optimal and ph is stable. I wouldn't try and change your ever ph, keep it what ever comes out of the tap. Rays in general don't like there ph or temp going up and down and flowers, well there difficult period. I would deffinely quarintine in bare bottom tank that you can get under and see if they are eating with no tank mates at all until they are eating, Flower ray are very shy and any food compition is not going to help. Also it sometime takes a long time for for them to start eating, don't panic just make sure you have lots of live blackworms on hand ( they work the best in most cases ) live worms small if the ray is small or cut in to bit size pieces for them and worst case scenerio one or both don't start eating right away within a week or so, seperate them, like I said earler they are very shy even to each other.
Temp should be 82-84 I personally don't believe in going any higher than that, all my tanks run at that all year round, stability is key with happy rays if your ph is abnormally high like over 8.4 you might want to look at a R/O unit and do a 50/50 mix with it, to soften water and lower the ph a bit but that only if you have a real high ph.
Breeding them has been very very very rare. They get extermly big 36"+ and mature very slow compared to other rays.
They do grow pretty fast though so i hope that you have a large foot print for your tank like at least 4x8 and to me thats not big enough for them for life.
Hope some of this help you out, Just have some paitents and everthing hopefully will work out.
