Id Shark Skin Condition

Hi, I'm hoping someone can help me. I've had two ID sharks for the past 15 years. 10 days ago I noticed a little white spot on the back of his neck. (pic 1) In time it seemed to spread and I went to the fish store to see what they could offer for treatment. (Pic 2)

They recommended Melafix and I administered 75ml per my 150 gallon once a day as of 6 days ago. I am noticing the abrasion to the skin is worsening, (Pic 3) I really am stuck as what to do. The fish has also lost a lot of weight but he does continue to eat and swim. He isn't acting as though he is sick but his skin looks like its worsening. I have attached a few pictures in its stages it's even worse today than in picture 3

About a week prior I added 2-small flying foxes 2-mid sized pleckos and 3-small "doctor fish" the flying foxes were nibbling at the dead skin coming off the ID shark and recently I have found the 2 flying foxes and 2 of the 3 doctor fish dead (the third seems to be Mia) the pleckos are fine and all my original fish seem to be fine. It total I have 2-ID sharks 2-clown loaches 2-silver dollars and one spotted catfish (all previously mentioned are 10-15 years old) with the two newer members being the pleckos - Tank size being 150 gallons

Any help would be greatly appreciated

ID Shark? is this an Iridescent Shark - Pangasionodon hypophthalmus
 
These guys grow pretty big!
3 feet according to SF for in captive species
 
"Unsuitable for all but the very largest tanks. It’s a very active open water species and tends to be skittish when kept in cramped conditions. This can lead to problems with the fish banging into the tank glass and items of decor, often resulting in injury. For even a single specimen to be housed long term a tank measuring at least 15′ x 6′ x 6′ (450cm x 180cm x 180cm) – 14,580 litres would be the minimum needed. Juveniles can of course be grown on in smaller tanks."
http/www.seriouslyfish.com/species/pangasionodon-hypophthalmus/
 
As for the skin id of what wrong, not entirely sure to be honest, have had quick look online for anything similar but nothing conclusive.
 
Looks like rotting skin, which could be sign of bad water quality, parasites, columnaris, ulcers that ulcerate into a hole.
 
And one last thing, Clown loaches and Silver dollars do much better in groups of at least 6+, am sure you were aware of this though.
 
Good luck.
 
 

Thanks, having started the hobby 15 years ago I wasn't aware nor did anyone tell me that these fish grew so large. I thought they were the cutest things and at 2 inches I didn't think I'd still have them at 16inches.
Anyways, I'm thinking it shouldn't be a parasite because my other fish would be effected, fungas? Does fin rot start at the fins? Because his didn't start at the fin (pic 1) nor are his fins affected Water quality is fine, have had it checked...

They are annoyingly cute at 2 inches. It may well be that the missing fish have been eaten, as they are quite predatory.
 
I'd go with ulceration from either a wound on some decor, a fight between them, or water quality issues (even temporary ones from things like leftover bits of food).

Thanks, any ideas on what my next step should be? Start the Metafix again? Bacterial, fungas meds?
Prior to the Metafix last week I did a 30% water change and did the Metafix for a week than a 30% water change and haven't medicated yet In hopes someone would have an idea of what my next step should be
He still continues to eat and swim, other fish still have no sign of issues.
The dead fish I found and pulled out

I'd go for a two step approach, firstly lots of clean water, bigger changes than 30%, go for 70%+ if you can, and more regularly than you normally would. In my experience it's worth far more than most other things.
 
Secondly you need to do two things, which are to make sure you're entirely clear what you have on your hands there with a positive ID of which type of fish you have, and then make a plan for the long term. If it's a Pangasionodon hypophthalmus then you're going to have some major problems coming up anyway in the future, and planning now will make things far less painful then. You'll probably be looking towards commercial aquaria as being the only places that can give them a good life in the longer term.

Oh I know exactly what it is, Iridescent Shark, Pangasianodon hypophthalmus. Their life expectancy is 20years, my two are 15 years old @16 inches. I doubt I'd have major issue with them shooting up drastically in size at this point but if they do i will take care of it
Anyways back to my major issue, I will do another water change even though my levels are ok, think I should start with Metafix again?
What's your take on aquarium salt? Someone recommended giving him a "salt bath"

The third pic with the redish patch in the middle, does this have a cauliflower like appearance to it? it could be lymphocystis, which is a virus..
 
http/www.aquarticles.com/articles/management/Lawler_Lymphocystis.html
 
and around it could be a fungal infection, which is why the melafix is not doing anything. If it is lymphocystis there is not alot you can do other than keep the water exceptionally clean to try and stop any secondary infections while the virus runs its course. If you can get esha 2000 I would recommend using that as it is a good all round med.
 
I am not 100% sure it is, just suspicious from that last picture.

Thanks, sorry about the pictures. In cropping them to fit into the post It lost resolution. Shame I couldn't attach the video I took, it shows it very well. The red spot is where i believe he had shortly bled from.

I did read the link you supplied and according to it, it will run its course. Hopefully that's what it is. I have searched online for local stores carrying the esha 2000 but unfortunately I haven't found any here in Canada.

Perhaps I should try a fungal medication, (API)? it won't hurt any of the fish and at this point I don't know what else to do other than water change. While adding water conditioner, stress coat and perhaps holding off on the bio support for now

Maybe try uploading videos to youtube and posting the link here, and for photos use a photo sharing website like photobucket and post the link here.
 
I cant add anything else that hasnt already been said besides  something i can tell you dont want to hear, you have 2 silver dollars when you really should have 6+ and yo have 2 clown loaches that should be at 6+, i realize you have had these fish for a long time and probably wont add or take away any of the fish in your tank, but id just like you to consider doing so, for the well being of the fish.
 
Do you know what species of plecos you have? And what exact name your one spot catish is? I only ask because these also may raise problems in your tanks, besides them pooping a ton and raising ammonia levels.

If it does look lumpy then it might possibly be lymphocystis, or a tumour if it has been bleeding. Sorry I wasnt sure if you could get esha 2000 in Canada or not. 
 
Looking back at pic 1 (forgive me I have never kept these fish) Under the white spot and slightly left looks like a lump under the skin. Then comparing that to pic 3 it looks like that lump that is now showing is in the same spot. I have been staring at the two pics for some time. Lymphocystis would appear in a scrape, wound or abrasion - which was my first thought thinking the white mark was a wound allowing the lympocystis in which then grows on top of the skin. The more I compare the pics the more I am thinking tumour as it looks like it has burst through the skin creating the white area around (either bacteria or fungal infection)
 
[SIZE=13.63636302948px]If it is a tumour there is not a lot you are going to be able to do I am afraid. By all means try and antifungal med to try and clear up that white around the site, clean water (as in fresh water ) will help with any bacterial problems, I would go 10-15% daily water changes (if possible) and monitor by taking daily pictures if the site is getting smaller.[/SIZE]

Not sure which bumps you're seeing, he has lost a lot weight so he looks lumpy from his bones
I think this is what I'm going to do..... 20% water change, administer the water conditioner and stress coat hold off on the bio support and treat with anti-fungal. Think its ok to do ant-fungal right after the water change or should I wait a bit?

Oh blimey that is getting big quickly! that is totally different to pic 3! OK forget lymphocystis or tumour - so sorry the pictures had me totally going down the wrong track
 
Is there any signs of any access slime on the rest of his body, eyes etc???
 
It could be extremely fast acting costia
 
http/www.fish-disease.net/diseases/costia.php
 
Also info on this site, which mentions using melafix to treat
 
http/www.aboutfishonline.com/articles/costia.html
 
I am sorry, pic 3 had me thinking wrong, it is so hard to tell sometimes from pictures.

Hi, I went to the fish store again and asked about costia and the guy said costia would be all over the body and not contained to one are. They didn't have the medications in the article from the link you sent His thoughts are the whiteness is fungal and suggested going with APIs triple sulfa in conjunction with
E.M Erythromycin
Any thoughts?

, Its why I asked if there was any other slime coat etc over the rest of his body, so Costia is out.
 
The whiteness to me looks like dead skin. I have to admit I have not seen anything like this,  I have no experience with those medications I am afraid, but if they do fungal and bacterial problems combined then you have no choice really but to go for it as the fish is going downhill fast with the rate that is going.
 
Sorry I am not being much help