im gonna be realistic and say it is a goner as well. This tank is too white with those rocks (not a stable old system) and appears to also be a fluval 13.5 or similar so stock lighting is usually too little. Sebae anemones are tough enough to get in healthy condition as it is, but that one appeared to be bleached already when you got it so it could have just been on the decline from when you bought it
I would see if anyone with an aged tank (like 4+ years) wants to take it nearby and can rescue it for you, but sebaes are hard to keep when received bleached
and wow on the fluval 13.5 guess that’s what it is. However the tank is about 5+years old but…
recently robbed all but one small rock from that tank and my others to stock and build my new 65gal setup.
I ended up putting a pair of clownfish in there for now, i think they are a bonded pair and my son bought me the anemone wanted to see if they would host it .
ammonia is showing 0.
Should I do a full range or test or think it’s ok.
not your fault at all and most likely guess, like i said before, it was most likely a goner. Sebae are hard to come by in good condition, most come in pretty bad shape and waste away.
Lol, im getting good at spotting the 13.5 now, so many people on here have one