is this normal for my nem?

Hi, i have a nem that has been in my tank for over a week, never inflated since. he still has color but won’t stick to things that well. no open mouth but swollen, it goes swollen and back to normal but won’t eat. i don’t know what to do. I’m doing a water change today to bring the nitrates down.

light: kessel A360W
water parameters:
ammonia: 0ppm
nitrite: 0ppm
nitrate:20ppm
calcium:380
alkalinity: 9
ph:8.2
phosphate:0
salt:1.025
temp:78

20 gallon truvu with 2 black ocellarus clowns, 2 domino damsels, watchmen goby & pistol shrimp, 6 blue legged hermit crabs and pearly jawfish.

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