HELP! Thesis fish are sick! (Flukes?)

[Pomatomus]

Sorry for the long post, but this is really important. If these fish die I may not graduate this year.

I am using Gulf flounder (Paralichthys albigutta) for my thesis. When I got back from the holiday break I was informed that one had died and none of them were eating. They are all breathing heavily and have pink mouths. Some also have pink around their bodies, particularly the fins. Now three have died in the past 2 weeks; the most recent was a jumper that had bloody patches on its (functional) dorsal side. The ventral side looked normal. I have attached pictures of the jumper and some closeups of his skin using a dissecting microscope.

During the autopsy I found an isopod and two gill flukes (I believe). They were all embedded in the mouth tissue, but not actually in the gills. I have attached microscope images of the parasites.

Now I can see that my largest specimen, a 19" monster has a number of them in his mouth. He is looking really bad and is only half-buried in the sand. I am thinking of surgically removing the parasites, or maybe a freshwater dip. Please tell me what you think, I hope to do this within an hour or two!

Lupin I need you!

 

[Pomatomus]

ttt

 

[Lupin]

Impressive necropsy you've done to find out the deeply rooted cause. Not many would have done the same way you did. The white parasites appear to be Achtheres strigatus. I have very limited experience in the saltwater field so I enlisted the help of my friend whose husband is a marine biologist.

The treatment she recommended are EITHER of the following:
1. Praziquantel and copper sulfate. Prazi for flukes and copper for the other parasite. Copper is not safe for SW inverts so treat the fish separately.

2. The other is dimilin. I'd call the company who manufactured the med you bought from for instructions on using it as SW treatment. Possibly not safe for inverts either.

 

[Pomatomus]

I forgot to mention that the copper concentration has been 0.75ppm for the past 4 days.

I lost the fish about 5 hours after surgery yesterday. He was swimming around fine for a while. The fish was held in a net and five of the "gill maggots" were removed.

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Lupin, thank you for your information. When researching these parasites I was lead to believe that these are not the "harmless" Achtheres; they more closely resemble the notorious (and apparently hard to treat) Ergasilus.

Another necropsy revealed I had missed two more parasites. The specimen was a 19" female with an empty stomach. It seems that no other parasites were found, except for some egg-like objects in the heart cavity. I have attached a picture and I plan to pick up my microscope pictures of them today. The scary thing is, under the microscope they seemed to move! The heart is in the center and the "eggs" are to the left.

 

[kendragon]

This is common in the koi hobby.
Both are crustacaen parasites - Argulus (fish lice) and Lernea (anchor worm). The lice is the round one and the anchor worm is the other in your pic.
They cause ulcer disease such as Aeromonas and Pseudomonas which infects the skin and cause ulcers (red patches).

 

[Lupin]

Doesn't look like anchorworm to me. I've encountered anchorworms before and that is not exactly what I found them to look like. You may be right about its close resemblance to ergasilus. I may need to confirm this myself.

Are the flounders under SW condition? I was looking at this thread from a different perspective because of my limited experience in SW but now that you mentioned it, I looked closer and one of them does closely resemble the fish louse and could be one.

Perhaps, we need to switch meds to dimilin (diflubenzuron) but if this is under SW conditions, I'd look for the actual dosing schedule differently than one recommended for FW use in case it works differently for SW.

 

[zpetrichko]

looks like good eatin!

 

[Pomatomus]

They do taste very good!

You are correct Lupin, they are completely marine. Does dimlin work in SW as well? A couple of websites I looked at recommended dosing with potassium permanganate. I found a jar of it in the lab; nasty stuff. It's corrosive, a strong oxidizer, potentially explosive, harmful to the environment, causes chemical burns, and is fatal if swallowed.

Anyone have experience with this stuff? I did a 400 gallon water change last night to begin the copper removal.

 

[Pomatomus]

Update:

One more specimen has fallen. The back was covered in bloody patches so we decided to anesthetize and perfuse it.

However, four of the individuals have started eating again. I added some activated carbon to remove the rest of the copper. I checked a LFS today and they don't carry dimlin, so I am thinking of using the potassium permanganate.

 

[Lupin]

I'm not sure I like the idea of using PP. It burns their gills. I'll have to email my friend about this again.