Ameobic Gill Disease (AGD); and addressing it in a display

estanoche

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Hi Channel!

I'm digging deep for ideas on ways to address Amoebic Gill Disease in my 190 gallon display tank. Here is the story:

Tank type: Reef (Coral, Inverts, (fish have been removed)
Volume: 190 gallon + sump ~ 250 gallon total water volume
Filtration: Typical skimmer, chaeto reactor, currently also running a 40W UV sterilizer to address parasites which is fed by a MJ1200
Lighting: (shouldn't matter but its radions)
Established: Jan 1 (tank is new); this disease was introduced to the system on 2/27 with the addition of (I hypothesize) a clam that was not freshwater dipped that came from a mariculture environment (retained water in clam introduced the AGD)

Recent parameters (APEX monitoring and salifert testing)
Temp - 75-77 degress, PH - 8.0 - 8.15 daily, ALK - 8-9, CA - 420-440, Nitrate - 16, PO4 - .12

STORY:

The disease was first introduced to this system on 2/27 with the addition of some new livestock (likely contaminated water in an maricultured clam) - at the time, we diagnosed and approached this issue as marine velvet. Fish lost within 10 days of introduction of the source included: 1 Kole Tang (deceased Day 7 post intoduction), 1 Powder Brown tang (deceased day 9) ,1 oscellaris clownfish (deceased day 10). 3 fish showed little/no symptoms and were removed from the tank (1 scopas tang, 1 yellow halichoeres wrasse, and 1 watchman goby), and treated with a formallin bath (2 hours therapeutic) and immediate placement in hyposalinity hospital tank (where they currently remain and are happy and healthy, also novel fish introduced to this hospital system have not shown any distress of disease)


We did not biopsy the gills at the time of the losses (couldn't find our/were honestly too lazy to find our microscope). Plan was to run a fallow period, and to prove that we had MV, sent a water sample to Aquabiomics for disease DNA testing. This water sample was pulled while the 3 (now) surviving fish above were still in the tank to ensure that we captured the ailment. Test results were returned with no presence of MV, but instead AGD (results here - https://aquabiomics.com/wp-content/uploads/simple-file-list/reports/estanoche/1001635_tankDNA.html).

Good news, treating the fish like they had velvet appeared to be a good course of action. But, the disease remains in the display. (here are the surviving fish in hospital from today, just because its nice to see them!)


So, the question - how do you address AGD in a display with invertebrates in it? From what I've read, a FALLOW period is not the solution, as it is a ubiquitous parasite. In fisheries this is treated in pens using freshwater holding for say, a week at a time.

Current ideas:
- H2o2 full tank treatment, coupled with the current UV
- Run a DNA test again and see if 30 days of UV to this point has done the job
- Just start over / freshwater sanitize the entire system (of course preferably not)

Display (today, has been fishless since 3/16)
20240426_112641.jpg
 

Jay Hemdal

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estanoche Welcome to the Fish Disease Treatment and Diagnosis Forum!

The #fishmedic team and other knowledgeable members of our community will do our best to help you resolve your questions. Please provide as much of the following as you are able:
  • Brief description of the issue you are observing and answers to the following questions:
    • How long have you had the fish with the condition?
    • Did you quarantine with medication when you first acquired the fish? (If Yes, which medication?)
  • Current water quality measurements
  • Clear photos of the issue taken using WHITE light and/or a short video of any behaviors (post in your response or on YouTube).
If you can help us by providing as much of the above info as possible, it will make diagnosing and providing recommendations for treatment MUCH easier! The Fish Medic team will get back to you as quickly as possible. In the meantime, other members of our community may also share their experience with similar situations and advice that they may have regarding your situation.

You may also feel free to provide a more detailed description of the condition if you wish to share more info than the above list.

Additionally, these links may be useful while you await a response:
 

Jay Hemdal

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Some follow-up questions:

The two hour formalin bath, what was the concentration?

Gross visual symptoms on the powder brown are classic for long-term Cryptocaryon. Obviously a skin scrape would be more definitive, but I cannot account for Crypt. not showing up in the microbiome sampling - any ideas?

What dose are you treating the H2O2 with? Do you have low range test strips to monitor that?

AGD is tough. I've only seen it in freshwater systems that had high bio loading...and then, it was not visible on gross necropsy (not to my eyes anyway) and only showed up in the histopathology results. The only symptoms the fish showed were "un thriftiness" and mortality.

Funny side note: the Wikipedia entry linked in your report is practically the same information as in Ed Noga's book - I think somebody just copied that over.


Jay
 
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estanoche

estanoche

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But yeah. Totally looked like another disease. This fish in the video had been in tanks for 5+ years; just moved to this system and had been in this system for 2 months; and the progression of initial symptoms to death was about 5 days; maximum.

Super fast. Nothing like ich I've ever seen.
The clownish lastest the longest after symptoms and didn't "give up" until about the 11th day post symptoms.
 
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estanoche

estanoche

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And I have not started any h2o2 dosing yet. Basically "trying to decide what to try" since the fish have all been removed and now I'm just in the "well what's next" phase of this relationship.
 

Jay Hemdal

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Given the fish had no visible disease I did a 25 mg/l bath for 2 hours. Following this http://fisheries.tamu.edu/files/2013/09/Use-of-Formalin-to-Control-Fish-Parasites.pdf

Formalin is dosed on a temperature/time/concentration basis. The typical tropical temperature dose is 15 to 25 ppm for a 24 hour bath. I use 167 ppm for one hour. I’ve not done two hour baths, but it would be around 75 ppm. You’ll hear 250 ppm talked about, but that should only be used in coldwater systems. I’d say that your dose was too low and short to have much benefit.
 

Jay Hemdal

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And I have not started any h2o2 dosing yet. Basically "trying to decide what to try" since the fish have all been removed and now I'm just in the "well what's next" phase of this relationship.
Dosing peroxide is often made to sound simple, but it is decidedly not. As an oxidizer, its reactive dose in the water is based on the organic loading of the water that gets oxidized first, leaving varying levels of unreacted peroxide. As the organics are oxidized, each subsequent dose of peroxide is less and less reacted, leaving more free oxidizer Therefore, the dose is variable. I use low dose peroxide test strips that I got off Amazon to help me adjust the dose. Don’t use peroxide if you have shrimp in the tank, they are very sensitive to it.
 
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