How long can a fish last without eating?

[Wishful]

Hi all
I have a Silver Tip Tetra that is unwell. This started just before Christmas, he stopped eating and started avoiding his Silver Tip girlfriend, when normally they spend an awful lot of time flirting.

Since we could see absolutely no symptoms apart from a raised respiratory rate and lack of appetite, we treated with Sabbactisun and Parazoryne alternately to see if that would cover off any bacterial or parasitical reason. No change. He has lost an immense amount of weight so that he is just a shadow of his normal self. We're now doing a course of Interpet Internal Bacteria medicine.

He shows interest in food, but frequently seems to approach a piece of food - actually take it into his mouth, but then he spits it out again. I've wondered whether he has some sort of blockage in there, but he's so small I wouldn't know how to remove it if there is - it must be pretty far back because it's not visible.

I can't help thinking he must be getting something from somewhere because he occasionally trails a sort of poo trail, although it nothing more than a whisp.

Any advice gratefully received.

Oh by the way, we do water changes every week, all the other fish are quite healthy and the water tests are absolutely fine - no change from the norm.

Thanks

Wishful

 

[WILDER]

If the fish hasn't been eating not a good sign, his poo won't look good if he hasnt been eating has there is nothing to produce, you probably wont find the cause now, I would of said try and anti internal bacteria med but you have done that, sorry the diagnosis is not looking to good, sorry, i no some fish can get a wasting desease.