had a silver aro jumped on me when i was sleeping, found it on the floor morning, already dried and was stuck on the floor. i literally have to pry it off the floor with a spoon and when i was doing it, the mouth moved. i dunno exactly how many hours was it on the floor but you can just imagine, it was that long! it was dried and stucked on the floor! anyways, i threw it back in the water, added salt, upped the temp and lots of air bubbles and powerhead. eyes were cloudy for around 2 weeks but it lived.
just make sure you dont stress it more by doing big water changes and being i a high traffic area. black arows are more skittish and tend to get stressed more than silvers so i would cover all the sides of the tank, thats just me tho, its up to you.
GL.