Foxface not eating

dgie31 · Feb 27, 2026

Having problem with this Fox Face been in the tank maybe 15 years and is not eating. Water quality good and no sign of him fighting others, any ideas?

tbrown · Feb 28, 2026

dgie31 said:
Having problem with this Fox Face been in the tank maybe 15 years and is not eating. Water quality good and no sign of him fighting others, any ideas?

Im not sure what's going on but I'm going to tag in @Jay Hemdal

Unit731 · Feb 28, 2026

I would suggest feeding live phytoplankton to offset any gastrointestinal malady. Herbaceous fish of this size can have a bad reaction to a diet consisting of preserved feed or even nori for too long. I hope it's not a Vibrio infection of ear. Good luck.

Jay Hemdal · Feb 28, 2026

dgie31 said:
Having problem with this Fox Face been in the tank maybe 15 years and is not eating. Water quality good and no sign of him fighting others, any ideas?

Welcome to Reef2Reef!

How long has the issue been going on? Was there a gradual onset of symptoms, or did it seem to happen all of a sudden?

Have you added any new animals to the tank in the past month?

Given the length of time you've had this fish, and the way it looks, my first thought is Mycobacterium infection. this is the number one killer of "old" fish - this bacteria is found in all aquariums, but really only causes diseases in old fish. Sorry, but it really isn't treatable.

Here is some text that I wrote about it:

Mycobacterium infection (AKA "Fish Tuberculosis") is a common, yet often misdiagnosed bacterial disease of freshwater and marine fish. It has zoonotic potential as it can infect humans through cuts in the skin.

Symptoms are varied and non-specific, and can include darkened coloration, popeye, emaciation, fin erosion, skin ulcers, and granulomas on the internal organs (which will stain for gram positive, acid-fast bacteria). In most cases, the disease is chronic and slow acting, with most fish succumbing due to "old age". However, in some species, held under crowded conditions, acute Mycobacterium infections have been seen, where a high percentage of the population will die, even at a young age. This has been noted in cichlids, pupfish, pirate perch and zebra danios.

Many treatments for Mycobacterium infections in fish have been proposed, but none work well. Antibiotics that have been used include erythromycin, kanamycin, and rifampicin. It is probable that any drug used would need to be dosed orally, especially if freshwater fish are being treated. Control is the best course of action; maintain optimal water quality, avoid overcrowding, and remove any dead fish promptly.

Atypical Mycobacterium, M. chelonae, M. fortuitum, M. marinum are very common in the environment, and therefore are found in aquariums. They are difficult to culture but can be isolated from virtually every aquarium if you sample properly. They are commonly found in frozen seafood items, so the chance of them being introduced into aquariums is consistently high.

Sterilization of infected tank decorations and equipment is difficult, and not strongly advised since these bacteria are already in the environment, but > 200 ppm sodium hypochlorite for > 1 hour has been shown to be effective (Noga 2010).