Was thinking the same thing, but it can be perfectly normal, so no need to scoup 10 000 meters down when you take out gravel, you will lose ALOT of beneficial bacteria.. A person who lives close to me once said that the surface area of stuff in the aquarium often saved people with not good enough filtration, since eveything in the tank keeps beneficial bacteria.. Keep her up and going, love here! And she does NOT seem skinny, she is just a small ray
Thank you and I just fed her some night crawler today and she loved them so they should fatten her up pretty quick she only about 6.5 inches across and she ate 3 cut up night crawlers
Here's a better picture of her and since I feed her she hasn't really left the bottom so I think she was just hungry and that's why she was swimming crazy all over the tank