I have 6 C. Sterbai in my 75g along with 4 angelfish and 1 Leopard Frog pleco. Yesterday I noticed 1 cory breathing VERY rapidly and hiding under the plants. I thought maybe it got spooked or something. Today, it's still hiding under the plants and still breathing rapidly. There is no other indication of anything being wrong with it (body color is great, no flashing, no red gills) and the other corys are acting 100% normal, it's just this one cory in particular. My water parameters are: 0 pmm Ammonia, 0 ppm nitrite, 10 ppm nitrate and 6.8 ph. Any ideas as to what could be wrong? Thank you for your help!