Majestic Angelfish fin disorder

[ss88]

Looking for some diagnostic input on a large Majestic Angelfish with progressive fin erosion.

Picture is of the specimen during a 3-minute freshwater dip in a red bucket. Note the erosion of the caudal, dorsal, and anal fins.

History​

• 8"+ Majestic Angelfish (Pomacanthus navarchus)
• Acquired from QM in mid-January 2026
• In my care for approximately five months
• Housed alone within its own compartment on a centralized life support system
• Other fish on the same system include an 8" Black Tang and a 14" Clown Trigger, neither of which are exhibiting similar signs
• Active, alert, feeding aggressively, and maintaining body condition
• No respiratory distress, flashing, scratching, or behavioral changes
• The Majestic's compartment is adjacent to the Black Tang's compartment. It is theoretically possible that the Black Tang's elongated snout could occasionally inflict mechanical damage through the divider, although this seems unlikely.

Quarantine / Treatment History​

• Copper maintained at 2.2 ppm for 30 days
• Hyposalinity at 12 ppt for 30 days following copper treatment
• Previous confirmed history of Cryptocaryon irritans and Neobenedenia prior to completing quarantine
• Freshwater dip performed today (3 minutes) with microscopic examination of the dip water. No visible flukes or other ectoparasites were observed.

Current Clinical Signs​

• Mild to moderate erosion of the caudal, dorsal, one pectoral and anal fins
• Mild localized body discoloration
• No obvious excess mucus production
• No visible external parasites

Water Parameters​

• Temperature: 80–82°F
• pH: 8.00
• Specific gravity: 1.021
• No activated carbon has been used while the fish has been in my care.
• Stray voltage measured approximately 0.2 VAC (essentially zero).

One possible clue is the timing. I've been reviewing archived, low-resolution security camera footage and, although the image quality isn't sufficient to be definitive, the fins appear intact approximately one month ago. Based on the footage, I believe the fin erosion and body discoloration likely began within the past two weeks. Unfortunately, I was away and unable to directly observe the fish for approximately the last 20 days.

About 30 days ago, I began feeding live Anole lizards to the Clown Trigger. I selected anoles because I assumed they represented a relatively low risk for cross-species pathogen transmission compared to live fish or amphibian feeders. I still believe the risk is probably low, but the apparent temporal association made me wonder whether I could be overlooking an opportunistic bacterial or parasitic organism capable of crossing from reptiles to marine fish. Has anyone encountered anything similar, or is that concern largely unfounded?

Another possible variable is inadvertent microbubble introduction from the return pump. The Majestic occupies the first compartment receiving supply water. I cannot confirm that significant microbubble exposure actually occurred, and I think gas supersaturation is unlikely because the air stones produce relatively large bubbles rather than a fine mist. Nevertheless, I thought it was worth mentioning in case anyone has observed chronic microbubble exposure producing similar fin erosion or skin discoloration.

At this point, my diagnosis possibilities include:

• Opportunistic bacterial fin erosion
• Mechanical trauma with secondary bacterial infection
• Nutritional deficiency
• Environmental irritation
• Chronic microbubble exposure
• Less likely, a residual or subclinical parasitic issue (the negative freshwater dip and microscopic examination make flukes seem less likely)

Has anyone seen a similar presentation in a large Pomacanthus? If so, what was the eventual diagnosis?

If this were your fish, would you pursue skin/gill scrapings, empiric antibiotic therapy, additional diagnostics, or continued observation at this stage?

Any input, particularly from those with experience managing large Pomacanthus or public aquarium collections, would be greatly appreciated.

 

[vetteguy53081]

Looking for some diagnostic input on a large Majestic Angelfish with progressive fin erosion.

Picture is of the specimen during a 3-minute freshwater dip in a red bucket. Note the erosion of the caudal, dorsal, and anal fins.

History​

• 8"+ Majestic Angelfish (Pomacanthus navarchus)
• Acquired from QM in mid-January 2026
• In my care for approximately five months
• Housed alone within its own compartment on a centralized life support system
• Other fish on the same system include an 8" Black Tang and a 14" Clown Trigger, neither of which are exhibiting similar signs
• Active, alert, feeding aggressively, and maintaining body condition
• No respiratory distress, flashing, scratching, or behavioral changes
• The Majestic's compartment is adjacent to the Black Tang's compartment. It is theoretically possible that the Black Tang's elongated snout could occasionally inflict mechanical damage through the divider, although this seems unlikely.

Quarantine / Treatment History​

• Copper maintained at 2.2 ppm for 30 days
• Hyposalinity at 12 ppt for 30 days following copper treatment
• Previous confirmed history of Cryptocaryon irritans and Neobenedenia prior to completing quarantine
• Freshwater dip performed today (3 minutes) with microscopic examination of the dip water. No visible flukes or other ectoparasites were observed.

Current Clinical Signs​

• Mild to moderate erosion of the caudal, dorsal, one pectoral and anal fins
• Mild localized body discoloration
• No obvious excess mucus production
• No visible external parasites

Water Parameters​

• Temperature: 80–82°F
• pH: 8.00
• Specific gravity: 1.021
• No activated carbon has been used while the fish has been in my care.
• Stray voltage measured approximately 0.2 VAC (essentially zero).

One possible clue is the timing. I've been reviewing archived, low-resolution security camera footage and, although the image quality isn't sufficient to be definitive, the fins appear intact approximately one month ago. Based on the footage, I believe the fin erosion and body discoloration likely began within the past two weeks. Unfortunately, I was away and unable to directly observe the fish for approximately the last 20 days.

About 30 days ago, I began feeding live Anole lizards to the Clown Trigger. I selected anoles because I assumed they represented a relatively low risk for cross-species pathogen transmission compared to live fish or amphibian feeders. I still believe the risk is probably low, but the apparent temporal association made me wonder whether I could be overlooking an opportunistic bacterial or parasitic organism capable of crossing from reptiles to marine fish. Has anyone encountered anything similar, or is that concern largely unfounded?

Another possible variable is inadvertent microbubble introduction from the return pump. The Majestic occupies the first compartment receiving supply water. I cannot confirm that significant microbubble exposure actually occurred, and I think gas supersaturation is unlikely because the air stones produce relatively large bubbles rather than a fine mist. Nevertheless, I thought it was worth mentioning in case anyone has observed chronic microbubble exposure producing similar fin erosion or skin discoloration.

At this point, my diagnosis possibilities include:

• Opportunistic bacterial fin erosion
• Mechanical trauma with secondary bacterial infection
• Nutritional deficiency
• Environmental irritation
• Chronic microbubble exposure
• Less likely, a residual or subclinical parasitic issue (the negative freshwater dip and microscopic examination make flukes seem less likely)

Has anyone seen a similar presentation in a large Pomacanthus? If so, what was the eventual diagnosis?

If this were your fish, would you pursue skin/gill scrapings, empiric antibiotic therapy, additional diagnostics, or continued observation at this stage?

Any input, particularly from those with experience managing large Pomacanthus or public aquarium collections, would be greatly appreciated.

Unfortunately the picture is of no help. Please post a video using bright white light intensity, no blue for best assessment. I also would refrain from feeding anoles who can carry mites and other environmental risks

 

[ss88]

I agree that the risk of interspecies pathogen transmission is extremely low. Most reptile parasites have life cycles that cannot be completed in a fully marine aquatic environment. Additionally, to my knowledge, reptile mites are commonly treated with freshwater immersion or baths, which would suggest they’re unlikely to persist on or infect marine fish.


The only reason I mentioned the anoles is because the timing appears to coincide with the onset of the fin erosion, although that may be purely coincidental.


Unfortunately, this clown trigger is an exceptionally finicky feeder and refuses virtually all prepared foods. At this point, it will eat little besides live prey.


I’ve also adjusted the image to better show the fin erosion. I don’t see the characteristic white or red margin that I would typically associate with active bacterial fin rot. Instead, the fins simply appear to be eroding, which is why I’m trying to determine whether this is mechanical, environmental, nutritional, or an atypical infectious process.if you look closely you will see 3 small sections of the tail fin with a scalloped shape removed.

 

[Jay Hemdal Verified Community Expert]

Looking for some diagnostic input on a large Majestic Angelfish with progressive fin erosion.

Picture is of the specimen during a 3-minute freshwater dip in a red bucket. Note the erosion of the caudal, dorsal, and anal fins.

History​

• 8"+ Majestic Angelfish (Pomacanthus navarchus)
• Acquired from QM in mid-January 2026
• In my care for approximately five months
• Housed alone within its own compartment on a centralized life support system
• Other fish on the same system include an 8" Black Tang and a 14" Clown Trigger, neither of which are exhibiting similar signs
• Active, alert, feeding aggressively, and maintaining body condition
• No respiratory distress, flashing, scratching, or behavioral changes
• The Majestic's compartment is adjacent to the Black Tang's compartment. It is theoretically possible that the Black Tang's elongated snout could occasionally inflict mechanical damage through the divider, although this seems unlikely.

Quarantine / Treatment History​

• Copper maintained at 2.2 ppm for 30 days
• Hyposalinity at 12 ppt for 30 days following copper treatment
• Previous confirmed history of Cryptocaryon irritans and Neobenedenia prior to completing quarantine
• Freshwater dip performed today (3 minutes) with microscopic examination of the dip water. No visible flukes or other ectoparasites were observed.

Current Clinical Signs​

• Mild to moderate erosion of the caudal, dorsal, one pectoral and anal fins
• Mild localized body discoloration
• No obvious excess mucus production
• No visible external parasites

Water Parameters​

• Temperature: 80–82°F
• pH: 8.00
• Specific gravity: 1.021
• No activated carbon has been used while the fish has been in my care.
• Stray voltage measured approximately 0.2 VAC (essentially zero).

One possible clue is the timing. I've been reviewing archived, low-resolution security camera footage and, although the image quality isn't sufficient to be definitive, the fins appear intact approximately one month ago. Based on the footage, I believe the fin erosion and body discoloration likely began within the past two weeks. Unfortunately, I was away and unable to directly observe the fish for approximately the last 20 days.

About 30 days ago, I began feeding live Anole lizards to the Clown Trigger. I selected anoles because I assumed they represented a relatively low risk for cross-species pathogen transmission compared to live fish or amphibian feeders. I still believe the risk is probably low, but the apparent temporal association made me wonder whether I could be overlooking an opportunistic bacterial or parasitic organism capable of crossing from reptiles to marine fish. Has anyone encountered anything similar, or is that concern largely unfounded?

Another possible variable is inadvertent microbubble introduction from the return pump. The Majestic occupies the first compartment receiving supply water. I cannot confirm that significant microbubble exposure actually occurred, and I think gas supersaturation is unlikely because the air stones produce relatively large bubbles rather than a fine mist. Nevertheless, I thought it was worth mentioning in case anyone has observed chronic microbubble exposure producing similar fin erosion or skin discoloration.

At this point, my diagnosis possibilities include:

• Opportunistic bacterial fin erosion
• Mechanical trauma with secondary bacterial infection
• Nutritional deficiency
• Environmental irritation
• Chronic microbubble exposure
• Less likely, a residual or subclinical parasitic issue (the negative freshwater dip and microscopic examination make flukes seem less likely)

Has anyone seen a similar presentation in a large Pomacanthus? If so, what was the eventual diagnosis?

If this were your fish, would you pursue skin/gill scrapings, empiric antibiotic therapy, additional diagnostics, or continued observation at this stage?

Any input, particularly from those with experience managing large Pomacanthus or public aquarium collections, would be greatly appreciated.

The picture colors are throwing me off. Can you post a video of the angel in-situ under white lights? I'd like to see more of how it is housed, as well as white light images of the fins themselves.
Can you describe the fish's feeding regimen?

When I've seen this on angels before, it's been due to mechanical trauma. That could be combined with some nutritional deficit that is hindering the repair of the tissue - I don't see clear evidence of a bacterial infection.

Regarding the trigger - I've never seen a clown trigger that required live food, they can always be trained onto something else. I think your trigger may be training you (grin). In thinking back, I've never fed reptiles to marine fish. Are you capturing the anoles yourself? Store bought feeder anoles are full of disease issues, including mycobacterium that *could* be transmitted to fish. In addition, I worry about a fish being able to digest scales and heavier bone.

I would think that any adverse affect from micro bubbles would cause more issues in the gills, or on the broad areas of the fish's body, not on the trailing edges of the fins. You can rule supersaturation out, it can cause chronic issues, but that is usually in the eyes, or bubble production under the skin. It may seem counterintuitive, but the presence of bubbles actually REDUCES the partial pressure of gas in the water, reducing the incidence of supersaturation (think shaking a can of soda).

 

[ss88]

To me, this is starting to look more like tankmate aggression. What are your thoughts?

The adjacent compartment houses an 8" Black Tang, and it's conceivable that the tang is taking opportunities to nip through the 1" diameter holes in the divider. The two fish spend a significant amount of time together along that divider, often occupying the same corner, so intermittent contact is certainly possible.

My plan is to install a secondary divider to increase the separation distance and completely eliminate the possibility of physical contact. If the fin erosion stabilizes or begins to improve after that modification, it would seem to support a mechanical cause.

If the lesions continue to progress despite eliminating that possibility, would it then be reasonable to consider an antibiotic bath, such as neomycin sulfate, or would you recommend a different treatment approach?

 

[ss88]

Regarding the trigger - I've never seen a clown trigger that required live food, they can always be trained onto something else. I think your trigger may be training you (grin). In thinking back, I've never fed reptiles to marine fish. Are you capturing the anoles yourself? Store bought feeder anoles are full of disease issues, including mycobacterium that *could* be transmitted to fish. In addition, I worry about a fish being able to digest scales and heavier bone.

I would be ecstatic to have this specimen accept frozen foods again. Prior to full-strength copper treatment, it readily accepted frozen foods. Since completing treatment, however, it has consistently rejected every frozen food I've offered.

The decision to use live anoles wasn't my first choice—it was a last resort after approximately three weeks of complete food refusal. During that period I offered a wide variety of frozen foods, including clam, lobster, crab, krill, octopus, squid, salmon, and several others, all without success.

While the fish was in hyposalinity (12 ppt), I intentionally avoided freshwater and brackish feeder fish because I was concerned about introducing parasites or pathogens that might tolerate those salinities. Anoles seemed to represent the lowest biological risk among the live foods I could think of, although I fully recognize they're an unconventional feeder. Yes they are hand collected locally and its very time consuming !

Now that the system has been returned to 1.021, I guess I do have additional options available, including freshwater feeder fish.

 

[Jay Hemdal Verified Community Expert]

To me, this is starting to look more like tankmate aggression. What are your thoughts?

The adjacent compartment houses an 8" Black Tang, and it's conceivable that the tang is taking opportunities to nip through the 1" diameter holes in the divider. The two fish spend a significant amount of time together along that divider, often occupying the same corner, so intermittent contact is certainly possible.

My plan is to install a secondary divider to increase the separation distance and completely eliminate the possibility of physical contact. If the fin erosion stabilizes or begins to improve after that modification, it would seem to support a mechanical cause.

If the lesions continue to progress despite eliminating that possibility, would it then be reasonable to consider an antibiotic bath, such as neomycin sulfate, or would you recommend a different treatment approach?

Fin damage can develop from rubbing, and that becomes a very real issue when housing fish in small chambers like this.

I’m having a hard time seeing how the tang could make targeted attacks against the angel without damaging its snout trying to reach it through the holes.

 

[KrisReef]

To me, this is starting to look more like tankmate aggression. What are your thoughts?

The adjacent compartment houses an 8" Black Tang, and it's conceivable that the tang is taking opportunities to nip through the 1" diameter holes in the divider. The two fish spend a significant amount of time together along that divider, often occupying the same corner, so intermittent contact is certainly possible.

My plan is to install a secondary divider to increase the separation distance and completely eliminate the possibility of physical contact. If the fin erosion stabilizes or begins to improve after that modification, it would seem to support a mechanical cause.

If the lesions continue to progress despite eliminating that possibility, would it then be reasonable to consider an antibiotic bath, such as neomycin sulfate, or would you recommend a different treatment approach?

Those do look like fin nips, I also cannot see how the fish next door would accomplish that but I would be very concerned about how they get along if they are ever living together without any barriers to prevent full contact? Could be just the current tight quarters are freaking out these fishes?

 

[ss88]

Fin damage can develop from rubbing, and that becomes a very real issue when housing fish in small chambers like this.

I’m having a hard time seeing how the tang could make targeted attacks against the angel without damaging its snout trying to reach it through the holes.

Fair assessment regarding the pectoral fin. However, the tail and dorsal fins appear more like scalloped nips than abrasion, at least to my eye. I’m not sure how rubbing alone would produce that pattern.


The fish is currently housed in a 24” × 18” × 18” compartment, which is roughly 30 gallons after accounting for the overflow compartment. The wide-angle camera lens makes the enclosure appear much larger than it actually is.


I also agree with your point that, if the Black Tang were attacking through the 1” holes, I would expect to see some damage to the tang’s snout as well. That said, I’m still trying to reconcile what would explain the scalloped appearance of the tail and dorsal fins, and why those changes seem to have developed relatively recently.


In the meantime, I’ll move the Majestic into a larger compartment and isolate it from the adjacent fish to eliminate any possibility of tankmate aggression.


Just so I’m clear, based on what you’ve seen so far, would your recommendation be to continue observing after increasing the compartment size, rather than initiating antibiotic treatment at this point?

 

[vetteguy53081]

Fair assessment regarding the pectoral fin. However, the tail and dorsal fins appear more like scalloped nips than abrasion, at least to my eye. I’m not sure how rubbing alone would produce that pattern.


The fish is currently housed in a 24” × 18” × 18” compartment, which is roughly 30 gallons after accounting for the overflow compartment. The wide-angle camera lens makes the enclosure appear much larger than it actually is.


I also agree with your point that, if the Black Tang were attacking through the 1” holes, I would expect to see some damage to the tang’s snout as well. That said, I’m still trying to reconcile what would explain the scalloped appearance of the tail and dorsal fins, and why those changes seem to have developed relatively recently.


In the meantime, I’ll move the Majestic into a larger compartment and isolate it from the adjacent fish to eliminate any possibility of tankmate aggression.


Just so I’m clear, based on what you’ve seen so far, would your recommendation be to continue observing after increasing the compartment size, rather than initiating antibiotic treatment at this point?

Continue observing and for improvement to skin

 

[Jay Hemdal Verified Community Expert]

Fair assessment regarding the pectoral fin. However, the tail and dorsal fins appear more like scalloped nips than abrasion, at least to my eye. I’m not sure how rubbing alone would produce that pattern.


The fish is currently housed in a 24” × 18” × 18” compartment, which is roughly 30 gallons after accounting for the overflow compartment. The wide-angle camera lens makes the enclosure appear much larger than it actually is.


I also agree with your point that, if the Black Tang were attacking through the 1” holes, I would expect to see some damage to the tang’s snout as well. That said, I’m still trying to reconcile what would explain the scalloped appearance of the tail and dorsal fins, and why those changes seem to have developed relatively recently.


In the meantime, I’ll move the Majestic into a larger compartment and isolate it from the adjacent fish to eliminate any possibility of tankmate aggression.


Just so I’m clear, based on what you’ve seen so far, would your recommendation be to continue observing after increasing the compartment size, rather than initiating antibiotic treatment at this point?

Yes, I don’t see signs of bacterial infection here, the margins are scalloped, smooth, without the tattered look of infected fins.

 

[ss88]

I have continued to observe progressive fin erosion in this specimen over the past few months. It had been housed in a compartment measuring approximately 30 × 18 × 22 inches. Its appetite had already declined before I transferred it to a second isolated holding system on September 28, 2026, and it has refused food since October 1, 2026.

Over the past two months, there has also been noticeable weight loss, particularly evident around the nape. I estimate its weight at 350–400 grams. Approximately three weeks ago, I attempted oral treatment with metronidazole. Initially, I was hopeful because the fish accepted the medicated food, but it subsequently refused further doses.

I moved the specimen into the 90-gallon holding tank with the intention of administering metronidazole baths, followed by praziquantel, to address possible internal parasites. Another possibility I have considered is ingestion of a foreign body. I have encountered this in angelfish before, with the ingested material discovered during necropsy.

For additional context, this specimen was allegedly collected in Micronesia. I have also considered possible cyanide exposure during collection, although I am unsure how well that explanation fits the collection location and the timeline of its decline.

At this point, I am considering forced feeding and if required anesthesia using MS-222. Any advice on further diagnostics or treatment would be appreciated.

You can review this link below for current images of the specimen.

Images of Majestic Angelfish

 

[W31Olds]

I would rule Cyanide out. Large Angels are not collected with it, and it's been too long since your initial Thread. I think the confined space is part of the problem causing undue stress. I would also Suspect he may have Flukes. Angels are notorious for having them and Tattered Fins are a sign. Have you observed any of the other symptoms? I just got a Regal 2 weeks ago and sure enough, the little guy has Flukes. He's only 3" long and in a 40 Gallon Breeder. A large Angel needs room and a place to feel secure. I also am running a UV ( not during Prazipro) to help with Bacteria. I would probably start with Prazi or you could perform a FW Dip and see if his appetite improves. Angels seem to tolerate these well.

 

[Jay Hemdal Verified Community Expert]

I have continued to observe progressive fin erosion in this specimen over the past few months. It had been housed in a compartment measuring approximately 30 × 18 × 22 inches. Its appetite had already declined before I transferred it to a second isolated holding system on September 28, 2026, and it has refused food since October 1, 2026.

Over the past two months, there has also been noticeable weight loss, particularly evident around the nape. I estimate its weight at 350–400 grams. Approximately three weeks ago, I attempted oral treatment with metronidazole. Initially, I was hopeful because the fish accepted the medicated food, but it subsequently refused further doses.

I moved the specimen into the 90-gallon holding tank with the intention of administering metronidazole baths, followed by praziquantel, to address possible internal parasites. Another possibility I have considered is ingestion of a foreign body. I have encountered this in angelfish before, with the ingested material discovered during necropsy.

For additional context, this specimen was allegedly collected in Micronesia. I have also considered possible cyanide exposure during collection, although I am unsure how well that explanation fits the collection location and the timeline of its decline.

At this point, I am considering forced feeding and if required anesthesia using MS-222. Any advice on further diagnostics or treatment would be appreciated.

You can review this link below for current images of the specimen.

Images of Majestic Angelfish

I would also rule out cyanide, although this species is almost always collected with it, the time has been too long for it to be damaged by that - it would have either died or recovered by now.

Oral metronidazole is tricky - the dose needs to be around 1% by weight in the food. It is very bitter, and even at a normal dose, fish will try it once and then never again. That always happens if the fish is too high.

If you haven’t seen it, here is an article I wrote on tube feeding fish:

https://www.reef2reef.com/ams/tube-force-feeding-fish.808/

 

[ss88]

@Jay Hemdal, I read your article on tube feeding, and I agree that if the underlying issue can be resolved within approximately a week, it may be preferable to allow the fish time to recover and resume feeding voluntarily before considering assisted feeding.

I have performed more than 50 tube feedings, but my results using MS-222 have been mixed. I have frequently observed fish regurgitating food as they recover from anesthesia.

Yesterday, we removed the specimen from isolation for a physical examination and performed an endoscopic examination under anesthesia using a 2 mm endoscope. The stomach appeared empty, but we observed a localized green area that seemed associated with the stomach wall, possibly near the pylorus. I wondered whether this could represent bile staining, although fluid or mucus obscuring the lens limited visibility. I would appreciate your thoughts on what this finding might represent.

Our primary objective was to investigate possible foreign-body ingestion. I have previously seen an annularis angelfish ingest Poly-Filter material, subsequently refuse food, become lethargic, and eventually die, with the ingested material identified during necropsy. We did not identify an obvious foreign body during this examination, although visualization was limited.

Following the endoscopic examination, we administered metronidazole mixed with food through a feeding tube roughly 12 grams. Unfortunately, during recovery from anesthesia, the specimen regurgitated an unknown proportion of the medicated mixture, leaving us uncertain how much food and medication it retained.

Do you have a suggestion on food preparations to prevent regurgitation?

Could malnutrition be contributing to or exacerbating the erosion of the anal and tail fins?

 

[Jay Hemdal Verified Community Expert]

@Jay Hemdal, I read your article on tube feeding, and I agree that if the underlying issue can be resolved within approximately a week, it may be preferable to allow the fish time to recover and resume feeding voluntarily before considering assisted feeding.

I have performed more than 50 tube feedings, but my results using MS-222 have been mixed. I have frequently observed fish regurgitating food as they recover from anesthesia.

Yesterday, we removed the specimen from isolation for a physical examination and performed an endoscopic examination under anesthesia using a 2 mm endoscope. The stomach appeared empty, but we observed a localized green area that seemed associated with the stomach wall, possibly near the pylorus. I wondered whether this could represent bile staining, although fluid or mucus obscuring the lens limited visibility. I would appreciate your thoughts on what this finding might represent.

Our primary objective was to investigate possible foreign-body ingestion. I have previously seen an annularis angelfish ingest Poly-Filter material, subsequently refuse food, become lethargic, and eventually die, with the ingested material identified during necropsy. We did not identify an obvious foreign body during this examination, although visualization was limited.

Following the endoscopic examination, we administered metronidazole mixed with food through a feeding tube roughly 12 grams. Unfortunately, during recovery from anesthesia, the specimen regurgitated an unknown proportion of the medicated mixture, leaving us uncertain how much food and medication it retained.

Do you have a suggestion on food preparations to prevent regurgitation?

Could malnutrition be contributing to or exacerbating the erosion of the anal and tail fins?

I always assume any green staining is bile/gall bladder. Pretty common in fish that haven’t fed for awhile.

Regurgitation is very common, worse if you try to get too much food in at once, or don’t get the tube properly placed. I also use a very light plane of anesthesia, just enough to keep the fish from struggling too much. I’ve even free/handed fish in some cases. I used metomidate, but as I recall, the regurgitation was even worse. I’ve not tried eugenol, maybe that’s an option?

12 grams of food was about 10 ml then? That’s a bit more than I would have tried for this sized fish. How much of that 12 gram was metro? The oral dose is typically 1 to 2% of the food total. Now, that’s because it’s so bitter, the fish won’t eat it on their own at higher doses. I think you can go to 5% when tube feeding. I’m out of the office, so can’t check my formulary on that right now though.

 

[ss88]

Roughly 10ml.

Assumed the fish weighed around 350 grams.

At the moment only had seachem metroplex available, 70% metronidazole. that would be 35mg/.7= roughly 50mg to 70mg of metroplex was used.

I referenced page 407 of noga formula b. 100mg/kg.

I do see its possible to use up to 5g/kg. seems high, but if advisable. I can give it a go today ideally without anesthesia or very light anesthesia.

 

[Jay Hemdal Verified Community Expert]

Roughly 10ml.

Assumed the fish weighed around 350 grams.

At the moment only had seachem metroplex available, 70% metronidazole. that would be 35mg/.7= roughly 50mg to 70mg of metroplex was used.

I referenced page 407 of noga formula b. 100mg/kg.

I do see its possible to use up to 5g/kg. seems high, but if advisable. I can give it a go today ideally without anesthesia or very light anesthesia.

I missed your last two questions earlier;

I try to make the food as thick as possible without it sticking in the catheter. I often just use flake food to make a sort of "pablum" or gruel. I'll mix up a batch and then "test draw" some - if it clogs, then I mix in more water and try again. I don't worry about trying to make the food wholly nutritious, it's just a vehicle to get the fish some energy, and in this case, meds.

Yes - long term nutritional deficiencies (including lack of protein) can cause the fins to not grow back normally. Since the fin edges are more rapidly growing than other tissues of the fish, poor growth will show up there first I think.

 

[ss88]

Unfortunately, the angelfish ultimately perished. During necropsy, I discovered two approximately 2 mm rounded, crystalline stones that appeared to be loose within the abdominal cavity, outside the gastrointestinal tract. The stones had a friable, sandstone-like consistency and were easily crushed. Interestingly, the gallbladder was difficult to identify. Given these findings, I suspect the fish may have developed gallstones, potentially resulting in gallbladder rupture, although I cannot confirm this. I would be interested to know whether anyone else has encountered similar findings in marine fish. I did not find any indications of internal parasite infections.

 

[Jay Hemdal Verified Community Expert]

Unfortunately, the angelfish ultimately perished. During necropsy, I discovered two approximately 2 mm rounded, crystalline stones that appeared to be loose within the abdominal cavity, outside the gastrointestinal tract. The stones had a friable, sandstone-like consistency and were easily crushed. Interestingly, the gallbladder was difficult to identify. Given these findings, I suspect the fish may have developed gallstones, potentially resulting in gallbladder rupture, although I cannot confirm this. I would be interested to know whether anyone else has encountered similar findings in marine fish. I did not find any indications of internal parasite infections.

Sorry to hear.

I’m out camping and couldn’t get your photos to load, but one image I saw looked like bile staining of some tissue, so that would line up.

I don’t know about gallstones in fish, but flashlight fish are often found with huge digenean worms in their gallbladders, so there is room for stones.