Well established blonde naso stopped eating

[Biff0rz]

I have a well-established, large blonde naso tang in my system, and over the past 2–3 days he’s completely stopped eating. This is very out of character for him. He’s normally the most aggressive eater in the tank-when I put in nori, he chases me around the tank and attacks the clip, and he bullies his way to the front when mysis goes in.

He’s also the largest fish in the tank at about 10" long. He’s big, healthy, and well-fed (I tried to capture that in the video), which makes this sudden change even more concerning. Now he won’t touch anything-no nori, no mysis, nothing else I offer.

On top of that, his behavior has changed. He’s been hiding under a ledge and isn’t swimming around much, which is unusual since he’s normally very active. I haven’t observed any aggression, and given his size, no other fish really mess with him.

Any ideas on what might be going on?

 

[Jay Hemdal Verified Community Expert]

I have a well-established, large blonde naso tang in my system, and over the past 2–3 days he’s completely stopped eating. This is very out of character for him. He’s normally the most aggressive eater in the tank-when I put in nori, he chases me around the tank and attacks the clip, and he bullies his way to the front when mysis goes in.

He’s also the largest fish in the tank at about 10" long. He’s big, healthy, and well-fed (I tried to capture that in the video), which makes this sudden change even more concerning. Now he won’t touch anything-no nori, no mysis, nothing else I offer.

On top of that, his behavior has changed. He’s been hiding under a ledge and isn’t swimming around much, which is unusual since he’s normally very active. I haven’t observed any aggression, and given his size, no other fish really mess with him.

Any ideas on what might be going on?

That’s a tough one.

The feeding slowed down and stopped over a few days or did it stop suddenly, from one feed to the next?

Was there any time where it showed interest in food, but didn’t eat, or tried to eat, but spit the food out?

The video doesn’t show much - there is a bit of skin issue on the right side by the lateral line, but that may just be an old mark.

The fish does look a bit subdued, like you said.

The tank looks great and the other fish seem fine.

 

[Biff0rz]

That’s a tough one.

The feeding slowed down and stopped over a few days or did it stop suddenly, from one feed to the next?

Was there any time where it showed interest in food, but didn’t eat, or tried to eat, but spit the food out?

The video doesn’t show much - there is a bit of skin issue on the right side by the lateral line, but that may just be an old mark.

The fish does look a bit subdued, like you said.

The tank looks great and the other fish seem fine.

He had some nori 3 days ago (ate like a monster) and then suddenly stopped eating. He's shown no interest in anything else since, not even attempting to eat.

So I've also noticed him being stressed - skin darker all over and flairing his fins. I also have seen him occasionally swatting at the glass. But I've seen him do that before but he still ate when he's done that before.

I'm not sure of the skin issue on the side, he doesn't fight w any of the tangs ever, those guys swat at each other but always leave the naso alone.

 

[vetteguy53081]

I have a well-established, large blonde naso tang in my system, and over the past 2–3 days he’s completely stopped eating. This is very out of character for him. He’s normally the most aggressive eater in the tank-when I put in nori, he chases me around the tank and attacks the clip, and he bullies his way to the front when mysis goes in.

He’s also the largest fish in the tank at about 10" long. He’s big, healthy, and well-fed (I tried to capture that in the video), which makes this sudden change even more concerning. Now he won’t touch anything-no nori, no mysis, nothing else I offer.

On top of that, his behavior has changed. He’s been hiding under a ledge and isn’t swimming around much, which is unusual since he’s normally very active. I haven’t observed any aggression, and given his size, no other fish really mess with him.

Any ideas on what might be going on?

Had this with my similar sized one a year ago. While breathing was not elevated, I did see flickering of upper dorsal and added PraziPro to tank and within 2 days began eating again. A video on your behalf would help to see if any notable signs but Prazi, being safe is worth a shot.

 

[Biff0rz]

Had this with my similar sized one a year ago. While breathing was not elevated, I did see flickering of upper dorsal and added PraziPro to tank and within 2 days began eating again. A video on your behalf would help to see if any notable signs but Prazi, being safe is worth a shot.

Are you thinking it's fluke related? I don't think I want to dose prazi in my display w sps. So it sounds like I need a hospital tank set up.

He's, he's been acting a bit stressed and his dorsal has been flairing.

 

[Jay Hemdal Verified Community Expert]

He had some nori 3 days ago (ate like a monster) and then suddenly stopped eating. He's shown no interest in anything else since, not even attempting to eat.

So I've also noticed him being stressed - skin darker all over and flairing his fins. I also have seen him occasionally swatting at the glass. But I've seen him do that before but he still ate when he's done that before.

I'm not sure of the skin issue on the side, he doesn't fight w any of the tangs ever, those guys swat at each other but always leave the naso alone.

I wonder if it got a blockage from the nori? That does happen, but usually, the belly shows some swelling.

 

[vetteguy53081]

Are you thinking it's fluke related? I don't think I want to dose prazi in my display w sps. So it sounds like I need a hospital tank set up.

He's, he's been acting a bit stressed and his dorsal has been flairing.

Video did not show flaring but Flukes as you may know not visible but can be irritating to certain fish. Presence of prazi will not hurt as in my case. Can I say prazi was the answer- May be coincidental but glad fish came back to normal.

 

[Biff0rz]

Happy to report he's eating again. Not sure what the root cause was but I will continue to monitor his behavior.