72F is ok for the cats, dojos, & white clouds, it's too cold for angels. I keep angels anywhere from 80F to 85F or better, depending on what I'm trying to accomplish with that tank. The problem you have is fish that need 2 different temperatures, corys, dojos, & white clouds like it cooler, 72F is fine for them. Cooler temps slow a fish's metabolism, this can lead to constipation in angels, as well as a decreased immune response to any infection.
Also, angels don't do well on a diet of strictly flakes, they need some brine shrimp, and occasional bloodworms as well. The corys & dojos need something more than shrimp pellets, corys love bloodworms. A happy medium for temperature would probably be around 77to 78F, and a higher protein diet would be appreciated by all the fish in that tank.
I would turn up the temp a little, and add some epsom salt. Epsom salt is different than aquarium salt, it won't harm the corys or loachs. If the angel doesn't make it, you can turn it back down to 72F, that is fine for the other fish.