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Cyphotilapia Species, Variants & Collection Points Discussion of Cyphotilapia frontosa & gibberosa Species, Variants & Collection Points.


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  #1  
Old 08-17-2012, 10:41 AM
jaideep
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Default Black Spots : Proof of being wild caught ??

Thats what I knew till today. That Black Spots was due to Nitrogen burning during the process of the fish being raised from the great depths & during transportation. Thus, it was a convenient way of labelling the fish as a WC. The other theory was that it was caused by certain parasites.

However, during my study on these fishes, I have come to know that these Dark Spots were not a proof of wild caught, its occurance varying by location. Nor was it due to the parasites, nor any scars (referred to as dead spots). And this appears worth believing. It is a type of melanoma, a skin disease similar to skin cancer. However, it is not dangerous, damaging or lethal to the fish, nor will it cause any inconvenience to the fish. The black spots are also common in some Tropheus variants.

Ref : Mopampa.nl
http://www.mopampa.nl/cyphotilapia-afwijkend-uiterlijk/
http://translate.google.com/translat...-inrichting%2F

Any other reference to what else it might be is welcome.
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Last edited by jaideep; 08-18-2012 at 12:10 AM.
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Old 08-17-2012, 11:34 AM
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To add to the above, I have read that UV radiation is one of the reason for Melanoma. IMO, it is quite possible that fronts/gibbs being deep water fish (implying low light & low UV) and whilst they are being raised to the surface suffer from the infection during transportation.

I again reproduce a excerpt from "Wavelengths effective in induction of malignant melanoma" by R B Setlow, E Grist, K Thompson, and A D Woodhead
"The action spectrum (sensitivity per incident photon as a function of wavelength) for melanoma induction shows appreciable sensitivity at 365, 405, and probably 436 nm, suggesting that wavelengths not absorbed directly in DNA are effective in induction. We interpret the results as indicating that light energy absorbed in melanin is effective in inducing melanomas in this animal model and that, in natural sunlight, 90-95% of melanoma induction may be attributed to wavelengths > 320 nm--the UV-A and visible spectral regions."

Now thats pretty close to the wavelength of the Actinic lights we use (And I use one too ), specially the pure Actinics (around 420nm).
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Old 08-17-2012, 01:16 PM
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I've yet to come across a conclusively authoritative explanation for the cause, just theories. Two theories I've dismissed in my own mind are:

Skin cancer, for exactly the reasons you stated, they live too deep to have that kind of UV exposure and if it was skin cancer why particularly cyphos and not many other Tang species, especially shallow water species?

Ammonia burn or anything else related to transport. Some who have been to the lake say this is not the case and that they come out of the lake that way-- and if it was due to transport than why do only wilds have the spots? (As far as confirmation of wild-- lake spots confirm wild but lack of them doesn't prove otherwise-- only some of them have it.)

Almost no one seems to mention this, but there is a scale eating fish, Plecodus straeleni, that mimics the appearance of cyphos and is said to mingle in with them to nip off their scales-- they have some nasty looking teeth. I have to wonder if lake spot indicates victims of this and results from scales injured in this way. This would explain why some cyphos have it and others don't, being a random event. Cyphos aren't their only targets, but might there be something species specific about their pigmentation/scale replacement physiology that results in the spots? Haven't come across anything to substantiate or disprove this, so just speculation on my part.
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Old 08-17-2012, 10:39 PM
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Wont argue for the sake of argument but more interested in knowing the truth.

WCs have lake-spots, whilst tank raised dont have them. The next logical question would be-
1. whether the lakespots were there when they were caught in their natural environment deep inside the lake ?
2. Did they appear when the fish were being decompressed at lower depths or during transportation ?

I too dont believe in Ammonia burns since the water is equally cycled even at the top and does not contain more Ammonia.
Parasites ? Not sure. But have they been identified, dont think so.

Is it just possible, that some cyphos have more of a tendency to get these UV burns leading to a Melanoma like condition when they are decompressed at upper levels (I suppose the decompression is almost for 24 hours or thereabouts) or being transported in open vats/containers ?

As to the question, why other fish dont have it, except for Tropheus as mentioned by the author above. Is it possible that Fronts being deep water fish (most others used in the hobby arent) never suffer from UV penetration at such great depths, the lighting itself being so low. When they are being hauled up, its just likely that some suffer from this disease. And as to why tank-raised dont have them - well, their genes are adjusted/altered to accept more lighting. So something like "getting used to the new environment"

JUST A THOUGHT
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Old 08-17-2012, 11:21 PM
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Not an argument as I perceive it, just stating our reasoning on something we can only speculate about, since as yet there isn't any real scientific answer, at least none that I've ever seen.

Not certain about whether lake spots have been specifically observed on cyphos living in their natural environment. Good question, though it might be hard to see them in underwater conditions.

But, back to theory of lake spots being skin cancer, the spots are considered harmless by any account I've ever heard and those fish go on to live healthy, normal (aquarium) lives. These fish are not dying from melanomas, etc., something that would certainly be a common topic for discussion (if not outright alarm) if it was otherwise. Neither are people finding it necessary to treat these fish for skin or scale issues or infections. For all practical purposes it's no more than a minor pigment oddity.

Now, I do know that some fish can be susceptible to sunburn, sometimes while other very closely related fish are apparently immune. But (at least according to what I've read) when this happens the skin itself is damaged and it's often accompanied by a fungus infection-- again, not something being reported in connection with lake spot.
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Old 08-18-2012, 12:06 AM
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Decided to to read some more on Melonama though the article never stated the Lake-spots as Melonama but "type of Melonama".

1. It appears, that not all Melonama are cancerous but may become cancerous with time as it penetrates the deeper layers of the skin.
2. Melonama on skin of humans is called Lentigo maligna melanoma or Hutchinson's melanotic freckle, a type of black pigmentation on the skin. "They appear in areas of skin that get a lot of sun exposure, so are most common on the face. They are also more common in people who have spent a lot of time outdoors. The lentigo maligna is flat and grows outwards in the surface layers of the skin. So it may gradually get bigger over several years and may change shape. If it becomes a lentigo maligna melanoma, it starts to grow down into the deeper layers of the skin and may form lumps (nodules)." Quote
3. It is also genetically passed on.
4. UV radiation from tanning beds increases the risk of melanoma
5. Melanocytes are cells that produce the dark pigment, melanin, which is responsible for the color of skin. They predominantly occur in skin, but are also found in other parts of the body, including the bowel and the eye (see uveal melanoma). Melanoma can originate in any part of the body that contains melanocytes.

The other alternative which I missed out is that these are genetical as a response of the fish to its environment. This is a very good article on fish coloration and pigmentation. http://www.wetwebmedia.com/AqSciSubW...coloration.htm

Ref Melonama:
http://cancerhelp.cancerresearchuk.o...noma#different
http://en.wikipedia.org/wiki/Melanoma
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Old 08-18-2012, 12:20 PM
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Funny, the more I think about this the less convinced I am by the skin cancer theory, insofar as it pertains to the collection of these fish. No disrespect, just different ways of looking at it.

But, two things occur to me. In some locations cyphos are not found very deep or are observed to come up to fairly shallow water at certain times of day or in certain locations. In fact, it's been said that at Kavala they routinely come to the surface to snatch scraps from fisherman, though I couldn't give you the original source of this observation. But it's difficult for me to see a strong case that simply bringing them to the surface would cause pigment abnormalities.

Even more convincing to me than the above is that we are not getting black spots in our tanks when they're in sunlit rooms or near windows, which mine are. In fact, I intentionally angle the blinds at the window next to my tank to bring sunlight into the tank and at a certain time of day sunbeams shimmer directly into the tank. My Kaps seem to like them and sometimes play directly in them and some of their best blues are when the tank is sunlit only (something others have also observed).

Actually, some research has shown benefits to UV exposure in aquaculture ponds (other studies have shown similar effects in natural environments) and some of our members have observed poorer results in a dark basement than in sunlit rooms, not that this is scientific. However, I've never heard of cyphos requiring special conditions in fish farm ponds that would eliminate sun exposure. (Though it's in connection with sun-overexposed fish farm ponds that I've read of certain species getting sunburned.)

Anyway, not that any of this conclusively settles the question of lake spot, it's just observation and my reasoning on it. Unless someone found where biologists have actually studied this and discovered the actual cause, about the only ways a hobbyist might prove something about it is if they were expert enough to biopsy the spots for themselves or motivated enough to take them for biopsy, then find something conclusive as to what they are.

Or someone could set up an experiment that exposes them to varying degrees of sunlight in an attempt to establish that this can actually cause the spots and at what intensity of exposure they appear, then again biopsy the spots to determine exactly what they are.
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Last edited by neutrinoman; 08-18-2012 at 12:50 PM.
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Old 08-18-2012, 12:45 PM
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in the tropheus world we call those black spot "OB" but i still have no idea where that comes from maybe someone on here knows the answer.

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Old 08-18-2012, 12:47 PM
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There's another possibility related to sun radiation, though, and it relates to their wild environment rather than collecting them. I won't make an extended post here and don't see the need to reference every statement, when you may well already know much of this and are adept at doing your own research. But the basics are:

Sun radiation better penetrates water at the higher energy (blue to ultraviolet) end of the spectrum. This is why it is blue at depth underwater, as opposed to red, for example. Fish are well adapted to this, many of them having quite good ultraviolet vision. (There is some study of fish with adaptations more for violet than ultraviolet.)

UVA and UVB have differing water penetration characteristics and the specific characteristics of the water itself (seawater vs. freshwater, for example) are also a factor. So, the subject becomes complex fairly quickly once you go beyond the basics. But if you do some research, UV radiation in nature is a biological factor at common cyphotilapia depths, in fact it's necessary to some organisms. (On a side note, the point is here again that cyphos habitat is not UV free.)

What some scientists are studying is the extent to which ozone depletion is affecting these environments biologically, including phytoplankton, biological cycles, etc. This also gets quite complex and some of it quite technical, so I won't make simplistic statements here or post a lot of references, but it seems reasonable to me to pose the question of whether or not it might be relevant to wild cypholitapia pigment oddities.
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Old 08-18-2012, 01:08 PM
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I think Forestcat in one of his post in this or another forum did show a F1 with Lake spots (its WC parents too had it). Other experienced members had mentioned that they too have seen Lake-spots in their tank raised F1's. Now, with such experienced members I am sure they can compare those spots with the Lake-spots and confer them to be the same, unless it was realised later not to be Lake-spots (since Forestcat didnt mention it as such later on). Also they are too experienced & commited in the hobby to have high Ammonia (Ammonia-burns) in their tanks. I believe that particular F1, belonging to Forestcat died later on.

So, we can confer that Lake-spot :
1. Not necessaily occurs only in WCs but also in tank raised
2. Its not due to Ammonia burns
3. There is a possibility that it is transferred genetically (Forestcat's Example)

So this has reduced the likely causes to reduce by some amount.
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