When should I be concerned about a fish not eating?

[hdemetri]

I just added a new chocolate mimic tang to my approx 168 gallon display tank 3 and a half days ago. It is a juvenile about 3.5 inches long and similar in size to my sailfin and hippo tangs that are established. There was minimal aggression from sailfin but a mirror calmed that down and I don't see any amount of concern. My ammonia is 0. Nitrites 0. Nitrate 5. I am feeding mostly LRS Reef Frenzy. Also adding frozen spirulina misus, frozen spirulina brine, PE pellets, garlic infused algae on clip, and some flakes. The new fish is occasionally pecking at he rockwork but not touching the food. It is a good looking fish with no spots or visual signs of disease. It does not look skinny yet but obviously I am concerned it can be prone to disease if it is not eating. I know it is typical for a fish to not eat when first introduced but when should I be concerned? All my other tangs ate a little bit on day 1 but it took a few week before they would eat vigorously. Should I just do as I'm doing for a few more days?

 

[Malum Argenteum]

Was it eating in QT?

 

[piranhaman00]

Pretty small tank for those fish, that won’t help.

 

[hdemetri]

Was in copper QT tank at fish store and I observed it eating mysis before purchase.

 

[hdemetri]

Pretty small tank for those fish, that won’t help.

You are right, especially if all 3 tangs reach max potential size for species. 3 tangs in 168 gallon tank is pushing it but I'd say any tang in any enclosure is not ideal. 3 juvenile tangs in this tank are not cramped right now, so the eating issue is probably not related to tank size.

 

[exnisstech]

The only suggestion I have is maybe rubber band a piece of nori to a small rock. It's how I started all of my tangs on nori before they would eat from a clip. All of the other food your offering would please any of my tangs so I have no other suggestions.