Color change  12/21/05
From the references in your excellent web pages on color in fishes, can
you tell me what the letters "TFH" and "FAMA" stand for? I'd like to look
up these references. <Richard, they are magazines.  Tropical Fish Hobbyist and Freshwater and Marine Aquarium.>
Thanks, <You're welcome.  James Gasta
Richard Ellis <<... THE R. Ellis? RMF>>

Ultrafluorescent  9/7/05
Hi friends:
We live in Baja Sur, Mexico... so far on the ocean at night, and not always there are special things that shines very brightly, specially related with the movement...nobody here knows the name of this parasites, fish, who knows.... They are supposed to shine more on bays, near the rocks or at the shore, but even if you inside the ocean they are by tons, they leave like a wave of glitter....so nice, so peaceful...
By any chance, do you know the name of these things?
We would appreciate your help
Regards
Hugo and Josefina
<There are many phosphorescent organisms in the sea... some are indeed spectacular... the most common in Baja are largely algae that "sparkle" when disturbed by surface activity. Bob Fenner>

The Ethics of Glo-Fish (TM) (6/5/05) Hiya Bob, <<Howdy. RMF>>
I just finished reading the article on the Glo-fish, and I was wondering if it would be possible to ask the author if he considers every breed of dog, most breeds of milk and beef producing cattle, and probably 80% or better of all of the grains and fruits he eats as also being 'garbage' due to the fact that they are also man induced 'mutations' (yes, the method may be different, but the intent and process is the same and similar-one is just more 'trial and error, after all, no?) For the record, I also don't like the idea of Glo-fish, or painted chandas, but plenty of folks hate telescopes, black moors, fancy guppies and swords for just as legitimate reasons. <Agreed> I can understand a POV of distaste and dislike, I was just wondering what selective bias the author uses to determine which of our obvious genetic alterations are 'garbage' and why? ;) (heh, maybe I should write a counter point article for submission, playing devil's advocate) <All submissions are welcome for consideration. You will have to use a lot better grammar than you did in this e-mail. Please capitalize the proper noun "I" and the first letter of sentences. We post all e-mails and replies. It's a lot easier for folks to read them if they are punctuated properly. If you do it then we can spend less time proofreading and more time answering.> Keep up the good work-been observing your website for years, all the best!
Alan
<Thanks. The author of the article is not a member of the question-answering crew, so I do not know how to contact him. I do agree with you on this issue. I have nothing against Glo-Fish (TM) myself. They were created to serve a utilitarian purpose (pollution detection). If there is a side benefit of providing pretty fishes that have not been chemically burned and dyed, that's great from my perspective. I have no problem with GM foods either. I say you're right that there is no difference in principle between this and selective breeding. It's only method and speed. In fact, GM is better because the planning will lead to fewer bad mutations. It just needs to be properly regulated. As for the other fish you mention, I have qualms about some of them. If fish are selectively bred for appearance, I only have a problem if that creates a deformity that impairs the fish or causes pain. Some of the fish sold these days definitely suffer as a result of their selectively-bred appearance. That's my opinion, for what it's worth. Steve Allen>

Question: behavior of color
Dear Dr. Fenner,
<Just Bob please, I have no doctorate>
I enjoyed reading your article on The Physiology and Behavior of Color in Fishes.
I am writing a children's book on albino animals.  I am trying to understand leucism, which according to my research
is defined as white or weak coloration.
What causes leucism?  Is it due to less pigment, less or abnormal chromatophores, or by the movement of pigment to different layers of the epidermis?
<Is of genetic disposition. A partial expression of color... imagine a multi-gene trait with only part passed on to offspring... and conditions allowing the presences of said young (most are eaten due to lightness of color by predators)>
Thank you for your time.  I appreciate your help and will give you credit in my book.
Sincerely,
Randi
<Thank you my friend. Bob Fenner>

Re: question: behavior of color
Hi Bob,
     Thank you for writing.
So, would I be correct in saying:  "In leucism, melanocytes function
abnormally.  Although the vast majority of melanocytes is defective, many
leucistic animals have certain areas of normal coloration, as in their eyes
or on their faces."
  Again, thank you for your help.
Randi
<Actually, no... the actual color cells that are present do function normally... but through inheritance, leucistic animals have partial to complete (even non bilateral) absence of said melanocytes. Bob Fenner>

Re: question: behavior of color 12/25/04
Now I'm beginning to understand leucism better, so that I can explain it to
children. Is it correct to say: Through inheritance, leucistic animals have partial to complete absence of
melanocytes.
<Umm, not absence... this is albinism>
Although there is a reduced number of melanocytes, many leucistic animals can make some melanin in certain areas, as in their eyes or on their faces.
<Yes>
I would like to credit you in my book.  Do you have a degree that I can add to your name?
<Not necessary, Bob Fenner>

Color Vision in Fishes
Hi gang,
The question just occurred to me as to whether fish in general and Tangs
of various varieties in particular are color blind. Nothing shows in
your data base. So, to your knowledge has anyone tested for this?
Regards,
Charlie H.
>>>Hi Charlie,
Yes, fish are equipped with both rods and cones, and can see color very well. Some deep water fish can only see in reds and greens - tangs, being surface fish can detect the entire range.
Jim<<<

Regarding Melanophores!
Hi there Dr. Fenner,
<Just Bob, or Robert if you must>
I emailed you once before about a month ago. In your paper on the Wetwebmedia website, do you know where you found the information on acetylcholine and epinephrine and its effects on the melanophores?
<Would have to search through the posted references... it's been a great while since I reviewed the root information>
Please email me back and help me!
Sincerely,
Nicole
<Are you able to search the literature... at a large (college) library? Bob Fenner> 

The Physiology and Behavior of Color in Fishes
Dear Dr. Fenner,
    I really enjoyed this piece and would like to give proper credit to you. Can you please email me the proper citation for this piece? Thanking you in advance!
Sincerely,
Nicole Hitchen
<Fenner, Bob. 2004. The physiology and behavior of color in fishes. Tropical Fish Hobbyist Magazine, Sept. 2004.>

The Physiology and Behavior of Color in Fishes 
Dear Mr. Fenner, 
<Ms. Palmer> 
I read your excellent article online at WetWebMedia and found it very informative- I would like to cite your work in a report I am doing on Zebrafish coloration and give you proper credit, but I am missing some key bits of information. Could you perhaps tell me when you wrote or posted the article, and if it was ever published in a non-internet source (and if so what that source might be)? 
<This small survey piece was written and posted just this last year... and did run in Tropical Fish Hobbyist Magazine... about six months back. Am out in HI or I'd look up the citation for you. Perhaps you can just cite WWM as the source with myself as the writer> 
I hate to impose but I would really like to give you the proper credit for this piece, it definitely helped me with my paper. Thank you very much for your time. 
Sincerely, 
Adriana Palmer 
Brown University, '05 
<Please make it known if I may be of other assistance. Will be back "home" in a week or so. Bob Fenner>

Fish Coloration - Why?
Dear Web Media,
Why do freshwater fish have dull dark backs and shiny silver bellies?  I am home schooled and have not been able to find the answer to this question.
Thank you.  From,  Jena Ritchey.
<Well, Jena, there are some very good reasons for this kind of coloration on fishes.  The silvery belly, when seen from below, blends in pretty well with the light color of the sky as seen from underwater, so predator fish might miss out on seeing their prey, or so the prey fish might miss out on seeing the predator sneaking up for a snack.  The dark color is harder to see from above, like from a fish-eating bird looking down, so the dark color will blend in with the mud, sticks, and such underwater.  Not all fish are colored like this, though; in fact, there are a few fish that are colored quite the opposite - with dark bellies and light backs - and swim upside down!  Most fish will turn very very pale at night, when it's too dark to see and their dark color isn't very useful.  There are also a lot of very brightly colored freshwater fishes in nature.  Some of these fishes come from muddy, cloudy waters, and are brilliantly colored so they can see each other and find mates; in these mucky waters, it's not as important to have the dark on top/light on bottom colors, because they wouldn't be very useful; if their predators can't see through the water very well to begin with, there's no reason to try to blend in, right?  Here's a link to a picture of one of many such brightly colored freshwater fishes:  http://www.fishbase.org/Photos/PicturesSummary.cfm?ID=53747&what=species Hope this sheds some light on things for you!  -Sabrina>

Question re behaviour
Dear Crew
<David>
This is probably a most fundamental question from a novice, and yet to date I have not heard a reasonable (informed!) answer to it:-
Q.  Why have certain genera of fish swim evolved to swim with a tail-down attitude - e.g. Nannobrycon and Thayeria and for that matter why do some swim with a nose-down attitude - e.g. Abramites?  The thought is that it is linked to feeding habits and yet it would seem to disadvantage such fish {compared to those that swim 'horizontally'}  should they require to escape rapidly from predators.
Yours sincerely
Brian
<Have not seen much (anything re spatial orientation function) and these Characoids (or other fishes for that matter) either. Will make some speculations. The parts of the world (Amazon et al. basins in South America) where these animals are found are relatively "old" and crowded relatively... and so as general rules go, there is more competition for food, space, avoidance of predators... Perhaps the "abnormal" positioning in the water column confers a benefit in not appearing like a food item? Maybe there is something to being able to escape up/down instead of ahead, to the right, left in avoiding "arrow shot" attacks by predators? Maybe something/s re these "tetras" markings, coloration and change therein matches with plant life, particle movement, light propagation... in their environment? Maybe it's time for you and I to make a trip to Brazil's outback? Bob Fenner>