New fish Not eating

[Charbel.eid9]

I got this fish from 3 weeks and it is not eating. All the other fishes are super fine eating normally and the water quality is very good. I'm feeding them Hikari medium floating pellets.
Every time I feed them the new fish goes behind the rock or doesn't react.
I started wondering if it eats special food?... And what is its ID?

 

[Termitehunter]

Aequidens rivulatus or Green Terror is the ID. Can be very aggressive as it gets older too.

Normally its a hardy eater. Did it eat at first? If it came from a LFS find out what they were feeding. Sometimes fish need to adjust or get used to what you do vs where they came from. If you have other aggressive fish in the tank it could be "shy" going for food. Especially if it's smaller than the rest.

 

[Charbel.eid9]

It did not eat anything since I got it. It chases the other fishes and looks great and energetic. The best thing to do is going back to the LFS as u said.
Btw, for how long can a fish stay alive without food?

 

[Termitehunter]

IMO that it can vary. Healthy fish can go longer I'm sure.
But after 3 weeks I'm thinking it must be getting nutrition somehow. Especially if its active. The longest I have ever heard of a healthy fish not eating is about 3 weeks before it died. Sick fish a week or 2.

I haven't let my fish go over a week because of vacation etc. So honestly, my thoughts would be a guess as to how long. Maybe someone else here has more info on that one.