Might be a couple of things going on here. Could be internal parasites and some constipation. Both often shut down a fish's desire to eat. Below are treatments from Humblefish's guidelines.
Internal/intestinal parasites:
Symptoms - Internal parasites are also “worms,” but these target a fish’s intestines. As a result, the main symptom is white stringy poop. It has to be white; brownstringy poop, for example, can just mean intestinal irritation which requires no treatment.
Treatment options - API General Cure (a medication containing both praziquantel and metronidazole). Some species of internal worms are resistant to prazi, while others are resistant to metro, but usually not both. :wink: Seachem MetroPlex can be dosed directly in QT, or soaking fish food with it provides an alternative (and reef safe) treatment option. Two other available options are: Paracide-X (mixed in food) and Paracide-D (in-tank treatment).
Swim Bladder Disorder/fish constipation:
Symptoms - Both of these have identical symptoms, but fish with swim bladder disorder generally do not survive. So your best bet is to treat for constipation and hope for the best. The fish will swim erratically, and appear to have difficulty maintaining its equilibrium. It may appear buoyant at the surface of the water, sometimes swimming in circles.
Treatment options - Feed 1 or 2 peeled boiled green peas (same kind you & I eat). Repeat daily even if the fish’s condition improves. The fiber contained in the peas will help “push things out.” If dealing with a fish that refuses to eat, you can try Epsom salt (as a laxative) or an antibiotic such as Kanamycin (aka Seachem Kanaplex) that lists diarrhea as a possible side effect.
Epsom Salt:
How To Treat - 1 tablespoon per 5 gallons of aquarium water. Repeat only once, if necessary. Use only “USP” grade Epsom salt.
Pros - Reef safe, as Epsom salt is just magnesium sulfate.
Cons/Side Effects - The effects of excessive sulfate in a reef aquarium are not fully known.
Internal/intestinal parasites:
Symptoms - Internal parasites are also “worms,” but these target a fish’s intestines. As a result, the main symptom is white stringy poop. It has to be white; brownstringy poop, for example, can just mean intestinal irritation which requires no treatment.
Treatment options - API General Cure (a medication containing both praziquantel and metronidazole). Some species of internal worms are resistant to prazi, while others are resistant to metro, but usually not both. :wink: Seachem MetroPlex can be dosed directly in QT, or soaking fish food with it provides an alternative (and reef safe) treatment option. Two other available options are: Paracide-X (mixed in food) and Paracide-D (in-tank treatment).
Swim Bladder Disorder/fish constipation:
Symptoms - Both of these have identical symptoms, but fish with swim bladder disorder generally do not survive. So your best bet is to treat for constipation and hope for the best. The fish will swim erratically, and appear to have difficulty maintaining its equilibrium. It may appear buoyant at the surface of the water, sometimes swimming in circles.
Treatment options - Feed 1 or 2 peeled boiled green peas (same kind you & I eat). Repeat daily even if the fish’s condition improves. The fiber contained in the peas will help “push things out.” If dealing with a fish that refuses to eat, you can try Epsom salt (as a laxative) or an antibiotic such as Kanamycin (aka Seachem Kanaplex) that lists diarrhea as a possible side effect.
Epsom Salt:
How To Treat - 1 tablespoon per 5 gallons of aquarium water. Repeat only once, if necessary. Use only “USP” grade Epsom salt.
Pros - Reef safe, as Epsom salt is just magnesium sulfate.
Cons/Side Effects - The effects of excessive sulfate in a reef aquarium are not fully known.


