Starfish dyin?

[Ruzoko]

My red knobbed started acting odd the last few days, started with partial hanging on the glass then he went back to the top and today hes at the bottom in this position. Fed him a shrimp a few days ago and been feeding it a chunk of food weekly. Urchin just went to steal the shrimp chunk the star didnt get fast enough btw.

Temp 76.5F
Salinity 1.025
PH 8.0
Ammonia 0
Nitrite 0
Nitrates 10 ppm
Alkalinity 8.5
Phosphate 0.16

 

[Ruzoko]

He got annoyed with the urchin and went flat >.> ignorin the 2nd shrimp piece i put by him too