Newbie clown

[UkAudi]

4 months ago I purchased 2 clownfish and up to a week ago they Stayed about 2/3 up then last Sunday one died (I treated the 90 gallon tank for red cyna with chemiclean)and the remaining one stays 90% on top back right corner except when I feed the fish, this short video and photo I was about to feed it, any suggestions welcomed, TYIA

 

[Webslinger]

they are called clowns for a reason.....strange fish