Elassoma Gilberti

A year from now when Erica's in NC we'll go catch some E. zonatum and she can begin her next 300 post thread.

In the event Erica's medical career takes her away from native fishes, the suggestion is being made to make certain extra effort is used to preserve this thread. It has been very informative and should be an ideal model for studies / reports on other species.

A year from now when Erica's in NC we'll go catch some E. zonatum and she can begin her next 300 post thread.

That would be fun

So, neat thing about the fry. At a certain age, they're iridescent:
 iridescent fry 2.jpg   93.74KB   0 downloads  iridescent fry 1.jpg   83.61KB   0 downloads
http://gallery.nanfa... fry 2.jpg.html and http://gallery.nanfa... fry 1.jpg.html

which makes sense if the fry is male, I guess,
because they never lose their iridescence as adults
no matter how much they try to blanch.
Pictures (two different ones): http://gallery.nanfa...ze_002.jpg.html
 blurry photo of iridescent male.jpg   48.5KB   0 downloads
http://gallery.nanfa...t male.jpg.html

Edited by EricaWieser, 15 February 2011 - 11:04 PM.

Oh yes, and here's a current photo of the tank. For once you can see a fish in it. She's floating in the right, in front of the myriophyllum:
 022resizetankphoto.jpg   204.24KB   4 downloads
http://gallery.nanfa...22_001.JPG.html <- Zooming in using that link shows more detail. Click on the picture and it gets bigger.

I remembered how to use the color filter setting so the plants look green again.
The murky stuff on the surface is a mixture of crushed flake food and the oils from a feeding dose of microworms. I only thought they were dead. They're not. *nods*

Edit: Oooh, using the zoom in I found another female blending in with the substrate in front of the rock statue. Neat.

Edited by EricaWieser, 15 February 2011 - 11:21 PM.

Skittish behavior: instinctual, learned, age related?

This is the crazy-active Elassoma gilberti that was raised with swordtail fry its size in a 10 gallon tank. It does not fear me and follows its reflection on the glass. Usually when an Elassoma gilberti sees me, they slowly slide back further into the plants to hide. This video might support the idea that their skittish behavior is learned, not instinctual. Or it could support the idea that skittish behavior is related to age, and that this is one of the ages where the gilberti is more active. I favor the first theory (socialization works) because there are a dozen other juveniles of this same age in the tank, none of whom actively nose the glass like this one.

Edited by EricaWieser, 16 February 2011 - 12:36 AM.

... or maybe a genetic mutation that makes her less fearful of open spaces and large moving things. A highly advantageous mutation in captivity (get more food and get chosen for breeding) and highly lethal in a wild fish. Some old-timer cichlid keepers have told me that firemouths and certain others that have been farmed for 50-ish years seem to have gotten meaner, presumably because aggression is much more important for survival and growth in a one-species pond than in nature.

Regarding E. gilberti, I've been keeping them for many generations (sometimes with Heterandria or other tiny fish, but mostly alone) and never had one that would follow me like a hungry swordtail. The best I get is a certain ones that slowly drift toward me if I'm not moving too fast.

PS - I don't think fish see their reflection in the glass normally. Stick your head inside the tank and look out. We see a reflection from the outside because the front and side glass panes makes a prism. Maybe if the room lighting is much darker than the tank lighting they can see a reflection.

Edited by gerald, 16 February 2011 - 09:40 AM.

... or maybe a genetic mutation that makes her less fearful of open spaces and large moving things.

Interesting. I hadn't thought of that one. I wonder how much genetic diversity remains in the gilberti that I have? They have been brother-sister bred for over a decade, right? Is it possible that they can still be distinct from one another? Or are they all basically copies of the same fish? I wish I knew more about genetics.

I started with 5 in 1999, and got a few new wild ones to mix in about 2004, 2006 and 2010 from various people. Ive tried to keep at least 3 pairs to breed each generation. So no, not all brother to sister matings, but a lot of cousin-to-cousin matings, so yes their gene pool may be rather shallow now. But I dont see why loss of genetic diversity would affect the mutation rate either way.

Interesting. I hadn't thought of that one. I wonder how much genetic diversity remains in the gilberti that I have? They have been brother-sister bred for over a decade, right? Is it possible that they can still be distinct from one another? Or are they all basically copies of the same fish? I wish I knew more about genetics.

Oh, I get it. This fish could be a first generation spontaneous mutation. I hope that's the case; then his/her offspring will be sociable, too.

You don't need a genetic mutation for a change to occur in your population. There are likely many genes involved in the social behavior of the population. What you are at risk of is losing some of the alleles that modulate behavior.

That being said, since your fish are just pets to remain in captivity, I wouldn't worry about it. It is just genetic drift and/or artificial selection towards the alleles that make the fish more outgoing.

Good point Laura - If this fish's odd behavior is due to genetics, it could just be a rare or rarely-expressed gene that's been in these fish all along. A low prevalence (or low expression rate) of the "fearless" gene could be important to long-term species success in colonizing new habitats. Obviously Mama fish doesn't want ALL her kids to act like that!

Oh my. I was reading the older posts back a page or so on this topic and just now compared the photos of the tank on February 10th to the tank on February 15th. That ceratophyllum demersum is pretty astonishing. It changed that much in five days. I think when I get home today I'm going to test the water for ammonia, nitrite, nitrate, and pH. I'm curious what that plant is doing to the water chemistry.

Feb 10th: http://gallery.nanfa...pixels.jpg.html
Feb 15th: http://gallery.nanfa...22_001.JPG.html
Look at the what happened to the center-most, bright red ceratophyllum after five days.

Edited by EricaWieser, 17 February 2011 - 02:25 PM.

Good point Laura - If this fish's odd behavior is due to genetics, it could just be a rare or rarely-expressed gene that's been in these fish all along. A low prevalence (or low expression rate) of the "fearless" gene could be important to long-term species success in colonizing new habitats. Obviously Mama fish doesn't want ALL her kids to act like that!

Actually, what I'm thinking is that there probably isn't a single rare "fearless" gene. It is probably the result of interaction between genes that modulate things like:
prey drive
hunger drive
don't eat me drive - other fish
dont eat me drive - birds/mammals
Territoriality towards males
Come-hither-ness towards females

There are probably more than one gene regulating those types of things as well.

Sort of like how we don't have one gene for height (short vs tall). A bunch of things come into play that produces a range of heights. We can select for tallness, say, and some of the alleles that reduce height can be lost. Tallness isn't rare, but just a certain combination of alleles.

So it isn't the expression of a single rare gene, but the expression of a combination of multiple alleles from many genes. Am I rambling or making any sense? I think I may need some afternoon tea.

Yeah, you're right, the short phrase for that phenomenon is polygenic, many loci affecting one characteristic. And one could get crazy and maybe invoke some kind of epigenetic phenomena, too.

I think when I get home today I'm going to test the water for ammonia, nitrite, nitrate, and pH. I'm curious what that plant is doing to the water chemistry.

Results:
pH: 8.0
Nitrate: 0 ppm (nowhere even close to the 5 ppm color)
GH: 22 degrees of hardness

I couldn't test for ammonia accurately because I think my test kit passed its expiration time (when I went to go open the chemical bottle there were a lot of crystals around the top and twisting the cap caused a lot of them to fall off. The concentration inside is probably not accurate after losing that much solute to those crystals). It's a safe bet to say that the ammonia would be at 0 ppm because nitrate was. Plants eat ammonia preferentially before they deign to use nitrate.

I'm surprised that nitrate is 0 ppm. I keep dropping big nitrogen sources into the tank. I feed enough crushed flake food to cover the surface of the water three times a day, I drop microworms and helpings of their mush bread substrate (a bacteria source for the infusoria, I figured) in there every day, and I feed the worms with sinking Wardley shrimp pellets daily. And still the nitrate is zero. ... I love my plant.

Photo of tank taken today:
 55 gallon tank Feb 17th 2011resize.jpg   203.91KB   0 downloads
http://gallery.nanfa...h 2011.jpg.html

And this male, he thinks he blends in with the kitty litter substrate:
 040resize.jpg   206.01KB   0 downloads
http://gallery.nanfa... photo.jpg.html

So it isn't the expression of a single rare gene, but the expression of a combination of multiple alleles from many genes.

I get it. It would be nice if, over time, more of the fish became fearless.
Maybe the reason why this one fish is sociable is because it already came from a line that had been bred in captivity for a decade, with the selection geared towards being less timid. Gerald, do any of the fish in your population ever do that thing at the front of the glass shown in the video?

The blue sparkle on the female's cheek separates Elassoma gilberti from Elassoma okefenokee:
 066resize.jpg   150.83KB   0 downloads  069resize.jpg   139.31KB   0 downloads  070resize.jpg   117.37KB   0 downloads  071resize.jpg   137.26KB   0 downloads
http://gallery.nanfa...resize.jpg.html
http://gallery.nanfa...resize.jpg.html
http://gallery.nanfa...resize.jpg.html
http://gallery.nanfa...resize.jpg.html

I'm trying to convince myself the females are cute. *sighs*

Edited by EricaWieser, 17 February 2011 - 10:41 PM.

 group photo resize.jpg   233.16KB   0 downloads
http://gallery.nanfa... photo.jpg.html
 face to face.jpg   136.25KB   0 downloads
http://gallery.nanfa...o face.jpg.html

I fixed the dead hyperlink to the picture of the Elassoma gilberti size comparison with Lymnaea snail:
http://gallery.nanfa...arison.jpg.html

That is interesting behavior the way the gilberti buzzed the front of the tank. Nativeplanter is right about it not being just a single gene, or allele. Many regulatory genes work together to regulate behaviors. Some variants will inhibit characteristics while increasing the propensity for another. Then others will have opposite inhibiting and increasing trait effects to varying degrees. Somewhat like balancing the air flow rate from a single pump through multiple airstones. Turning one valve effects the air flows through the other stones. That is the best analogy I can think of atm. In the wild the optimum balance of behavior tends to be fairly strictly regulated. In captivity these variants are allowed to survive and even thrive over the wild variants. So, in a sense, genetic diversity can actually increase over the wild population. Of course if you are only talking about a single specimen there is no genetic diversity, regardless of the genetic heritage.

The way gerald described moving in some new blood over time is fine. Inbreeding has the potential effect of knocking out genes entirely, sometimes used for this explicit purpose. As long as breeding pairs are most probably removed from siblings by a few generations (cousins), with an occasional outside genetic infusion, there should be no real concern about long term genetic issues. At least not for pets. Just do not expect them to be fit for survival in the wild, but that has nothing to do with a loss of genetic diversity in general. Rather a change in the balance of regulatory genes.

I hope you can get a more domestic line of gilberti from it .

Fish reflections <off topic>:
The question of fish seeing reflections of themselves in the tank is interesting to, at least to me. Under some circumstances a fish should be able to see its reflection. Though probably at an angle to itself, rather than straight on. This is a quantum effect of light when passing a surface where the index of refraction changes. The reflectivity will cycle between minimums and maximums as the glass thickness increases, and glass at an angle is effectively thicker than glass straight on. Negative index of refraction materials (metamaterials) is used for all sorts of very weird effects.

There is a weird, somewhat related, experiment you can do with three polarized lenses. A polarized lens will pass 50% of the unpolarized light that hits it straight on. So a second polarizer at 90 degrees to the first will block all light that hits it. Yet you can take a third polarizer and place it in between the first two, at 45 degrees to them, and 25% of the light will pass through those three lenses when it would not pass through two of them. These quantum effects are related to the weirder non-local effects you may have heard about. It seems that light behaves this way even when the information that defines how it behaves is too far away and happened too fast for information to get there at light speed. Yet the randomness insures the only way to read the information is to wait on a regular light speed signal to decode the faster than light information. If anybody peeks at the information before it gets there it will be lost. So it is being developed as a "full proof" encrypted communication channel, physically impossible to intercept spy on.

Anyway, given the right light sources and angles a fish should be able to see reflections just like we can. Though more likely a reflection of the background off to one side. Fish might even chase the reflection as it seems to keep the same distance, like trying to catch a highway mirage while driving in the summer heat.

I get it. It would be nice if, over time, more of the fish became fearless.
Maybe the reason why this one fish is sociable is because it already came from a line that had been bred in captivity for a decade, with the selection geared towards being less timid. Gerald, do any of the fish in your population ever do that thing at the front of the glass shown in the video?

This is an interesting topic. I was reading an article in the latest issue of National Geographic about a Russian project over the last 50 years to domesticate the silver fox through through selective breeding. The theory is that domestication is based in genetics. The fun part is that they now have foxes that are every bit as gentle and playful as labrador retrievers.

Harry Knaub