Suddenly a strict carnivore

So i have had this Desjardini sailfin tang for over 2 years and he has always gone after nori with great gusto. Over the last month he stopped showing interest in the seaweed but still eats when i feed the frozen food and pellets. Other than this, he still seems to be acting normally but does seem to have thinned a little. he has always been quite fat so i am obviously a little concerned. i have tried multiple seaweeds that he has eaten in the past and the powder blue is still eating so i don't think it is the food. Has anyone run in to a similar situation or have any ideas?

I know people will ask so my parameters haven't changed.

temp - 78.5 - 79.5
salinity - 1.026
ph - 8.0 - 8.3
nitrates - 0
calcium - 400
dkh - 11
mg - 1290

 

My naso quit eating seaweed for the most part as well. I noticed it recently. He destroys mysis, pellets, bloodworms, brine, etc... but will totally ignore my sheets of nori and the seaweed that comes in Rods veggie blend.

 

Semi-related. My Bangaii Cardinal suddenly refuses to eat mysis. Devours pellets. Had eaten mysis like a champ for 18+ months.

 

oddly, this same tang has never gone for mysis even though every other fish in the tank will.

 

All my tangs eat frozen and pellet and I own 6 of them. I wouldn't be concern. If I ate the same thing day in and day out I would change too.

 

Maybe he finally got a taste for Mysis and said... "damn this is GOOD! Why have I been wasting my time on this algae stuff!"

 

I just thought I would update this thread. Over the past several months, the Desjardini has gone back to eating the nori. never did figure out the reason for his fast. Maybe Computerjohn was right and he was just burned out. Anyway, i just pulled up this old thread and felt the need to close it out. I needed closure.