# why do some cichlids get nuchal humps



## lament configuration (Jun 22, 2003)

what is the difference between a RD or a Frontosa getting a hump and a JD or the Malawi eye biter not getting one? If its for dominance, wouldnt every species want to have a nuchal hump equivalent?


----------



## tweaked (Aug 3, 2003)

Mostly it's the males that get the large humps.


----------



## Poseidon X (Jan 31, 2003)

Females can get the same huge humps. Its genetics. Just like some humans are massive and others arent, with CAs the strong fish with the best genetics get the biggest humps. Even with selectvely bred fish like flowerhorns less then 15% of the total born population will have humps.. of that amount only 50% will be shapped correctly and an even smaller amount with have enormous heads. My new piece is getting shipped next week, at 4 inches it has a pingpong ball head







its gonna be enormous.


----------



## lament configuration (Jun 22, 2003)

so BDKING, does that mean that genetically, its possible for a jack dempsey to grow a nuchal hump? It just has to take place? I always was under the impression that only certain species got it, and I was just wondering why.


----------



## Poseidon X (Jan 31, 2003)

well look at dovii and green terror.. in the home they get non.. in the wild they get huge humps, convicts too. plus hatians.. they are all nandopis speciies


----------



## piranha45 (Apr 8, 2003)

Poseidon X said:


> well look at dovii and green terror.. in the home they get non.. in the wild they get huge humps, convicts too. plus hatians.. they are all nandopis speciies


true

I imagine JDs just never get humps in the wild, either. Too bad I dont think anyone but a professional researcher could explain why JDs lack them.

Oscars don't have humps either; wild oscars totally lack humps


----------



## lament configuration (Jun 22, 2003)

So its more along the lines of just the majority of fish from CA having them with the exception of JDs and Oscars. Does this go for Africans as well?


----------



## Poseidon X (Jan 31, 2003)

hardly any africans have them.. but if you consider the fact that species on two different continents both developed these humps, there has to be some kind of distinct physicaly or physiological advantage of having them.


----------



## acestro (Jul 7, 2003)

Advantages suggested are either social (shows dominance, attracts mates) or actually have combat value.

Why some fish have them and some don't would best be looked at mapped on a phylogeny ("family tree") of cichlids. You could determine how many times it has evolved and demonstrate that (for whatever reason) some species have lost this ability to have nuchal humps or some have re-evolved it. Some may never have the genetic capacity to grow them in the first place, whether it's advantageous or not doesn't matter. Evolution can only work on what is there. Organisms do NOT adapt (actively) to environments.

The technical phrase would be "phylogenetic inertia", we can't grow wings in our backs because there's no capacity for it. We can't drop eggs and sperm into water and have little human babies fertilized outside of the body, our ancestry precludes it.


----------



## lament configuration (Jun 22, 2003)

Great answer acestro. Cleared up a lot of things.


----------



## acestro (Jul 7, 2003)

Very happy to help!


----------



## Poseidon X (Jan 31, 2003)

Thanks for the expert clarrifcation acestro. The hump is very mysterious, and whether someone things it looks good or not it sure catches the eye. I like to think that the fish with the biggest egos get the largest heads.

This is my new baby awaiting transportation from cali to me
Super big head red dragon.























He is about 4.5-5.5" with his tail hes over 7" right now.


----------



## acestro (Jul 7, 2003)

Although I prefer natural fish that is one impressive animal. Good luck with him.



> I like to think that the fish with the biggest egos get the largest heads.


Could be!

I'm not sure but I would guess the trait is hormone mediated (High testosterone=larger hump). Fish actually have a different kind of testosterone (11-K-T) but it works the same way as us. So, a lot of "T" equals a lot of aggression/ego as well as some physical characters....possibly!


----------



## piranha45 (Apr 8, 2003)

BD how much did u pay for him?


----------



## Poseidon X (Jan 31, 2003)

top secret, believe me i paid alot less then he is going to be worth... one with this kind of potential could turn into a champion. Your basic red dragon at 4" is going for $225. RDs with huge heads seem to be alot more rare then blue dragons with heads.


----------



## Poseidon X (Jan 31, 2003)

acestro.. totally agree with your interpretation. If you can ellaborate on how testosterone operats in fish i would be very interested. There is one more nice piece that actually has slightly better markings then this one and de, eper red, but the head isnt as big. Hes really nice though exoticflowerhorns.com, fhimports.com also has some next generation red dragons in stock


----------



## acestro (Jul 7, 2003)

It's actually quite interesting and complex how it acts in fish. 11-K-T (11-keto-testosterone) can affect aggressive behavior as well as breeding coloration/size/etc. These things are called "secondary sexual characteristics", the primary characteristics are basic things (like testis).

For example, you've probably seen some electric blue african cichlids that were blue at 1". These are obviously hormone treated fish. The problem is the color will fade. Why? That is the really cool question. Parts of the brain are also involved and it's only when these are locked in that the color in these haps stays.

Flowerhorns are interesting to me. I would guess aggression and traits that go with aggression have been selected for (color, size, nuchal humps), creating a natural 'supermale'. As with any lineage with selective breeding there may be other negative aspects but that's been covered here before (I think...).


----------



## Poseidon X (Jan 31, 2003)

that intresting, the same thing could be achieved with any specimen by selective breeding. Right now the market is very different in the usa then in asian countries. In the united states, and lfs stock 100s of cichlids packed into tanks. I have a problem understanding this because the lfs does not service enough people with large enough tanks to hold multiple cichlids. What does this lead too.. the unknowing customer says, wow these are nice fish.. i think ill buy 5 of them, and the lfs is happy to sell. Indirectly, i think this way of running the aquarium business results in animal cruelty. In asian markets, only the very best specimens leave the breeding farms. These fish have a much higher price because of the processes involved, eventually they become extremely nice... just like the selectively bred super red texas which is incredible.. This thai fish is in even more demand then flowerhorn throughout thai land and selling for very high prices. I would like to see US breeders take the time to assure the quality of all their fish, grow them out and only sell a few of each species at the fish store at a size where one can compare their quality to others.


----------



## lament configuration (Jun 22, 2003)

Article on nuchal hump from "the cichlid room"


----------



## acestro (Jul 7, 2003)

> Indirectly, i think this way of running the aquarium business results in animal cruelty. In asian markets, only the very best specimens leave the breeding farms.


A good point. however.........I have also heard that the 'rejects' of this selective breeding have been dumped into local waters in Asia and now they have a potential issue with exotic cichlids. If only we could take the best of both continents (not that there aren't plenty of exotic cichlids in the U.S.!).


----------



## acestro (Jul 7, 2003)

Excellent link. Barlow is the champion of cichlid research. For lazy clickers here is the best part (in my opinion) from the link;

George Barlow and Paul Siri considered many possible functions for the hump. It could be an organ of fat storage, offer mechanical advantage in fights, improve hydrodynamics, serve as an anti-predation device, or be the object of mate choice. First the researchers marshalled the facts. The hump changes size over time. It gets larger during courtship and actually shrinks during the parental phase. Males and females fight during the parental phase so if the hump was a fighting weapon, females should develop humps equal to those in males. Similarly, if the hump serves in fat storage or as protection from predators, why don't females develop them? Furthermore, the hump doesn't actually contain large volumes of fat, it is for the most part filled with water. The hydrodynamic explanation may apply to other kinds of fishes with humps (e.g., salmon), but the bulbous shape of the cichlid's hump is likely a hydrodynamic deterrent, if anything.

By offering female Midas cichlids a choice of rubber dummies of male Midas cichlids molded with differently-sized humps, Barlow and Siri found that females prefer males with humps over those without, but only up to a certain point. Once the hump becomes enormous, female preference declines. Several possible explanations exist. Hump size may serve as a measure of a male's condition or quality. Or, the hump may merely serve as a way to distinguish males from females. Many of the species with humps are highly monomorphic - males and females look alike - and the fact that the hump peaks in size at the time of pair formation strongly suggests a role in sex recognition. Nonetheless, the story is not finished because, as the researchers point out, well-fed fish develop larger humps: if sex recognition were the sole factor, the hump would develop to a specific size, but no further. The enormous humps seen on some captive males - and shown to be unappealing to females in the experiments - may not occur in the wild because it may not be possible for large males to afford such elaborate displays. Future experiments and observations will be needed to sort out the explanations for this intriguing character.


----------



## Lahot (May 20, 2003)

something I've recently noticed that might pertain to this discussion...

I had 4 frontosas that I bought with a friend in an attempt to breed them. One of the original males died, so I found what I was pretty sure was a male in a lfs and bought it and added it to the confirmed male and 2 females.

2 weeks ago, the remaining confirmed male died. Now the other smaller unconfirmed male that didn't have a flat head (but not much of a hump either) is starting to get a much bigger hump on his head.

I would think that since the larger 'alpha' male died, he's taking on the role of the alpha and his hump is growing as a result of this.

just an observation, no scientific proof behind any of it


----------



## Poseidon X (Jan 31, 2003)

wow that is great information... some intresting facts to point out that may be related to the hybridization of flowerhorns. there are female flowerhorns that grow enormous heads. Two hobbyist were conducting and expermient... called experiment X in which a female with a head larger then almost all males was paired with an equally massive male. This fish were both incredibly built, the nasty female took one hard shot at the male which sent him into shock, the blow was so bad that they seperated the fish and the male died within a few days.  
With FH anyway, it has been pretty much made a for gone conclusion that not all fish are going to get huge heads. They must first have the genetics to get such a head. You can subject males to the perfect condition and they will not grow a head 19 out of 20 times.


----------



## Poseidon X (Jan 31, 2003)

Acestro, i would like to post the info you found on our new www.flowerhornusa.com version 2 website... feel free to come by and contribute, during our grand opening. We welcome everyone, even critics, and would love for someone to give some scientific imput about the famous head which everyone there is infatuated with.


----------



## Poseidon X (Jan 31, 2003)

-delet me-


----------

