black slime on gills???

[MatsP]

Your water change sounds about the same as I imagine many others - I use RO water, which alters the process a bit. The only alteration (not that this would "improve" anything per se) would be to have a Carbon block filter or HMA (which is one particular form of Carbon block filter) to remove chlorine and heavy metals, etc - then you could add the water directly to the tank, rather than muck around with dechlorinator.

--
Mats

[Viktor Jarikov]

DJ-don, thank you! If it was in the water, then my RTC problems would be invariable and not depend on which tank/pond the fish are in, and would probably be almost invariable with respect to fishes meaning all RTCs would be affected one way or another, sooner or later, I naively think...

Mats, thank you. Helpful as usual! I did not put two and two together.. But then again, I may be steady but I am slow So this filter is kinda like the ones ("Brita" is famous here?) they hook up onto kitchen faucets to improve drinking water for human consumption, right?

[MatsP]

Yes, a Brita filter [according to Wikipedia the filter media in Brita is a Silver-coated carbon block filter with a ion exchange resin supplementary filter] is similar to the HMA filter, but the HMA is more suited for large volumes of water [and of course, cost a lot more, but over the longer term I believe it's less expensive]. The HMA doesn't have the ion-exchange resin.

--
Mats

[DJ-don]

ooo maybe you should try using some carbon in the tank!! that could actually help your problem.. cant believe none of us actually thought of that before

just make sure to change it once every 4 weeks

[Viktor Jarikov]

Thank you, gentlemen! I will look into that.

Now, DJ-don, you are changing/developing the subject, right? Mats and I were discussing water changes and absorption of chlorine and harmful metals by carbon, which we believe has nothing to do with my intermittent RTC die-offs. So you posit that it ALSO may help with the RTC problem in some unknown to us way. Hmmm. Good thinking.

To tell you the truth, I never use carbon in my tanks - I much much prefer to make use of the volume for bio filtering. How much carbon will a 2500 gal pond need every 4 weeks in your estimation and what's reasonable cost? Will I have to look for carbon in bulk?

[MatsP]

I did not mention adding carbon to the tank because I don't have carbon in any of my filters.

I feel that it's a pretty useless thing to have in a tank unless you have SPECIFIC things you want to fix:
1. Medicine removal.
2. Reduction of tannin (brown colour from plant/wood breakdown).

It may affect other things such as adsorption of hormones, and any heavy metals that were in the water and "neutralized" by the dechlorinator (thiosulfate solution), the carbon will adsorb that too. But assuming the levels of for example heavy metals is "sane" in the first place, I'd expect that carbon has little effect.

--
Mats

[Viktor Jarikov]

Mats, that pretty much sums up what I thought and think about carbon. Glad to see we thought alike, but still quite open to new knowledge. Still wonder too why the filter manufacturers are "pushing" carbon everywhere!!?? Is there any substance (other than trying to make a fool-proof filter) behind BIG claims of 3-stage filtration: look, people, you are gonna get a pristine quality water after bio, mechanical, and chemical filtration... And then people buy carbon all the time. In fact, I trade-in the carbon I get with my canister filters for something more useful for me and my main LFS gladly accepts it because people want it. Could it be mostly a hype?

[MatsP]

Carbon is added to the filters to keep the water from going yellow from vegetable breakdown. I put wood in my tank without soaking it for the "brown water" effect [and you should note that a lot of the filter companies will ALSO sell "blackwater extract", which is essentially tannic acids that colour the water brown]. And of course, it sounds good to say that it "takes care of" heavy metals and such things - which is a white lie in the sense that it's unlikely that the water has toxic levels of heavy metals, and there certainly shouldn't be anything in the tank that produces metal in the water, so it would have come from the tap-water if it's in there at all - and if that's the case, a HMA (or Brita) filter is the right solution.

--
Mats

[apistomaster]

The fish look a lot like those which have some form of hemorrhagic septicemia.
In most cases this is caused by bacteria but some fish viruses may produce similar symptoms and results.
These diseases are the bane of many aquaculturists from Trout hatcheries, Koi farms to food fish.
Most operators have to drain, disinfect and start all over again as there are no easy or practical ways or medications with which the condition can be successfully treated

The products which are supposed to deal with heavy metal ions in water use EDTA chelation but any water which is that toxic is not suitable for use nor a candidate for remediation using EDTA chelation
IMO.

[MatsP]

The products which are supposed to deal with heavy metal ions in water use EDTA chelation but any water which is that toxic is not suitable for use nor a candidate for remediation using EDTA chelation
IMO.

Would levels "unsuitable for use" be within the limits of the law in the US? I understand that the US rules (at least on nitrate - it may not be the case for heavy metals - I'll look it up later and post again) are stricter than those in the UK, and from memory/experience, the ACTUAL measured levels are normally far better than the levels allowed.

Edit: Viktor: in case you didn't know, you can get the water quality report [should be free too] from your local water supplier - just contact their customer support.

--
Mats

[Viktor Jarikov]

Larry: thank you much. So you do NOT believe it was the ~4' fall that killed my big RTC as it could not lead to such septicemia symptoms? It kind of makes sense to me, because these fish are built very tough, but then again, my thinking is worth little for the lack of solid grounds, knowledge, or experience. Well, if it was a bacteria or a virus, it has not (thank God!!!!!!!!!!!!) affected any other fish, including 3 other RTCs, in my indoor pond so far. All ate voraciously last Saturday, one week after my big RTC's passing. I hope and pray it never will affect them.

BTW: the talk about carbon, heavy metals between Mats, DJ-don, and me was just in general - at least, Mats and I do not think it has any ties to the RTC deaths. It's just that DJ-don inquired about my water changes.

Mats: as always, thank you much. The local water authority sends me (and everyone) an annual report and I save them but I do not know how to interpret the numbers because I need to know what the toxic levels are at least for the main several potential malfactors. There is a ton of numbers in the report. I can cite some numbers here?? Just let me know what metals and/or substances?

[MatsP]

Well, I don't think it's heavy metals, but if you can list things like:
lead
copper
aluminium (or however you want to spell it)

any others that you think look "interesting".

Also levels of "pesticides" (there is PROBABLY a group for that or something similar).

I think the key would be to take note of any that have:
1. levels close to the limit (they usually list what the max allowed level is next to the measured level)
2. those that vary a lot from "mean/average" to "max" (e.g. "average level = 2.03 ppm, max = 32 ppm, allowed level = 40 ppm" would be one to note as "possible problem").

I have no specific knowledge as to what toxic levels for tropical fish actually is - just that I expect the levels in your local water to be fairly low anyways, so PROBABLY not of any consequence here.

--
Mats

[Viktor Jarikov]

thanx Mats! Give me till tonight. The weather is nice outside and the backyard work is behind schedule...

[apistomaster]

Of course there are a few exceptions, in general the limits set by EPA for drinking water for any substance we would consider a problem in fish keeping are typically far below the allowable maximums.

[Viktor Jarikov]

Larry, I read it several times and still not completely understanding your wording. Could you please rephrase?

Also, a yes or no to the question at the top of page 3?

[MatsP]

Larry's reply says "The EPA rules would be fine for fish".

--
Mats

[apistomaster]

Hi Mats, Thanks.
The detailed reports generated by your water utility shows actual measured levels of all the minerals, metals and common industrial/agricultural pollutants and the EPA's maximum allowable limits.
Very few water utilities supply us with water which have contaminant levels anywhere near the maximum allowable levels. It is not uncommon for utilities to send out an abridged form of the comprehensive test results and it is sometimes necessary to request a copy of the detailed report.
That is how it works with my water utility. It is pretty rare to be sent water fit enough to drink but is not fit enough for fish as tough as large species of Catfish.

Of course a 4 feet drop on to a hard surface is enough to kill a fish. I use that method, with a little added acceleration, very frequently when I euthanize a fish.

I was under the impression that you lost more than one large catfish. The appearance of the fish in your photos did make me think of hemorrhagic septicemia. Unless one actually does an autopsy which includes microscopic examination of gill tissue, intestinal content, blood smear and so on(not going to explain the latter vague phrase), the possibility of parasitic flukes, tapeworms or nematode worms cannot be eliminated as contributing causes of death. The thinness of the fish certainly is consistent with parasitic infestation of some sort and can occur concomitantly with hemorrhagic septicemia.

[Viktor Jarikov]

Larry, thank you much! This post has two stages. The first one was a couple months ago when I lost all three ~1-2' RTCs that were in the pond over the course of a week. You firmly posited that this was some type of bacterial infection, suspecting the channel cats as possible carriers.

The continuation was tacked on last week when I lost the biggest one of the 4 RTCs (all new, of course) that were in the pond. This time, the big guy jumped out of the quarantine tank and was quickly scooped up and thrown into the pond only to die 3 days after - see the post, 1-2 page, for details. The second set of the pics is of him, of course. (The first set of pics is of the first RTC to die at stage one).

Now, your guess for the second set of pics is hemorrhagic septicemia. Just to note: The fishes' appearances differ vastly: for the first set for pics, the cat looks just fine except for the blackish slime abundant on his gills (post-mortum). This one looks a bit thin. The cat in the second set of pics (is not thin!) looks terrible all around but has no excessive slime on his gills, albeit his gills are blackish (see the post for details).

Are you sure you are providing your opinion on the second set of pics and not the first one (again)?

I am not sure what's confusing you at this point so am trying to recap the basics. Enough? Is the whole thing too much to read (e.g., just my posts)?

[apistomaster]

Nothing personal but I am not very interested in keeping large catfish in captivity so other than whatever I have written, I really do not have anymore to add that would be helpful.

[Viktor Jarikov]

Sure! And I appreciate it, Larry! I am just trying to understand and extract full value out of you have already written - education is of value when one grasps it. But please feel free to disregard my ranting and write as you please.
Best wishes! --Viktor

[DJ-don]

personally i dont use carbon at all because i have to replace it often and i find that wasting money and tedious.
but for your problem i thought it could help do something but i dont know the full effects of carbon. was just my suggestion.
maybe like what larry said it could be some form of bacterial disease??

again i dont know if this question has been asked or answered but what are the ammonia levels of water and nitrites? that could mean something..

[Viktor Jarikov]

DJ-don, I do not disregard your refreshing hypothesis that carbon may help, we are just saying that with the present knowledge expressed by Mats and Larry, it is hard to see HOW it could help. But you would be absolutely right if you said that more often than not, life is about trial and error and not about having solid reason-clad grounds for trying things.

The pH is ~7.2-7.4. NH3 ~0, NO2 ~0, NO3 ~5 ppm. Steady.

Note that the symptoms and the circumstances for the two deadly occurrences differ vastly: first 3 deaths two months ago vs the last 1.5 week ago. It does not appear sensible to me to lump the two, but our main powerhouse of knowledge, namely Larry, says (in nicer words than these) that he's lost interest and/or ability to help any further, not even clarify what he wrote before Oh, well. It's all good. Gotta learn to appreciate what you have and not dwell on what you do not have.

[apistomaster]

I merely made as many contributions as I could at a distance.
I felt I could not offer anything more that would help without doing some microscopic examinations of the tissues of the dead fish to see if I could detect any signs of parasite infestations. One can only tell so much from a gross examination of photos. So it isn't like I am holding back any information but that I recognized my limitations.

[Viktor Jarikov]

Hi Larry! I totally understand what you just said - you have said it a few times before and I feel bad that you felt that you needed to say it again. Sorry! What confused me is the last paragraph of your post on Mon Jun 21, 2010 6:35 pm (see above) - about the "impression..." and about the "thinness...". So I wrote a recap, to which you gave little reaction. Anyway, let's forget and move on, shall we?? Love your help any way and any time!
--
Viktor