# Yellow Calvus Now Black?



## jsaunsnp (Jul 14, 2008)

I have 5 Yellow Calvus, ranging in size from 3" -4.5" they are housed with 11 kitumba gibbs and a few plecos in a 100g 5 foot tank. They were on a white pool sand substrate for the last 8 months or so and always were a very colorful yellow with great striping. Approximately 3 weeks ago I switched to a black sand substrate and all 5 turned all black with no striping and no color? I did expect they would get a little darker but this drastic change has me a little concerned. Has anyone ever had this happen? Will they ever "color" back up? They are doing great otherwise, eating well and showing no signs of other problems. All the water parameters are good as well. Should I give them time, or move/sell them to get them on a different substrate?


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## BioG (Oct 12, 2008)

There are several reasons Calvus color up. Namely, spawning, fighting, camouflage and stress.

Your "Yellow Calvus" over black sand will, most likely, be blacker than they are yellow permanently. White Calvus will do the same thing.

In reality, The white and yellow Calvus variants are actually "white" or "yellow" in their neutral coloration or state. But over black sand, not only will their neutral state be perceived as darker (Probably at least as dark as their yellows are.), but when they're spawning etc. you'll probably not see much difference between them and their black cousins from Zambia, Zaire or The Congo.

However, when spawning, your yellows would have taken on an almost black color anyway. I have described all these colors, itp, as "modes". E.G. When a male is in his "Courtship mode", like when he's shaking in front of a shell trying to attract female attention he'll have his blacks and blues at full tilt (There are several body language displays which explain what "mode" they're in as well but I won't go into that here.)

Females for example usually start of courtship mode all colored up but once the eggs have been laid they tend to "go gray" or in your fish's case they would go neutral and therefore yellow. It, however, probably won't be the most stunning yellow as it will displayed as her basic or "neutral color". Sub males will also, generally display this if you're attempting to keep multiple males.

IMe, Yellows look best over natural sub. The good news is that regular play sand is cheap.

My point is that even though you've got "yellow Calvus" Yellow is there base color not their "Colored up" coloring. All Calvus color up the same, in black, blue and a little bright white here and there.

For example this is a White Calvus group over play sand and "Holey Rock". You'll notice that the two Largest Calvus were a spawning pair and thus darker whereas the two other females, which were not available for spawning/courtship at that time were stark white. I believe the coloration is part of what signifies availability etc. because a non-spawning female will go dark first and then the male takes an interest in courting. 








Nother thing is that, no matter what variant, they all get darker at neutral coloring as they get older so, if you wanna see what they'll look like at 7-10 yrs. old, put them over black sand.

You might say; That Male isn't THAT dark but he was, at the time of the photo, in what I call " Patrol Mode" and the female was only as dark as she was because she was in "shell guarding mode" and he was attempting to get too close. "shell Guarding" is the mode after the eggs have been laid and fertilized and when the female relentlessly defends the shell or cave, hence the "Shell guarding" moniker. During "patrol" and "Shell Guarding" their colors are on but maybe only by half... Perhaps to represent to other conspecifics what they're doing currently and thus to avoid any unnecessary physical confrontation, I don't know.

Here's a pic of that same male in full courtship coloration. Remember he's a wild caught, 5" White Chaitika Calvus!








And this is how he looks at neutral now that he's an old fish. (I've had him about 6-7 yrs and he's wild so he's gotta be 10 or so I should think. That is, based upon his size when I got him.)








HTH :thumb:


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## PaulineMi (Apr 3, 2008)

Interesting explanation BioG. My Calvus has always been the same color as the one in your last picture. When I got him he was the same size as my N. Brevis. He's about 2 yrs old now. Unlike jsaunsnp's tank, I have holey rock and natural colored gravel in the tank however my Calvus is the same size (3"). Based on your explanation is he actually the color he's displaying (as in "black cousins from Zambia, Zaire or The Congo") or could he change under different circumstances?

jsaunsnp...what do you have in the way of hardscape in your tank?


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## PaulineMi (Apr 3, 2008)

Ooops...I think I just found the info I asked about under the "Black Calvus" thread started by Dillon.


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## BioG (Oct 12, 2008)

Color wise, you'll find that they're variant (e.g. "yellow", "white", "black" etc.) label dictates the basic color that the fish will be in a settled and/or neutral state. Like the Milky white females in the pic above. They have defaulted to actually being "white" (As advertised) when they are not in the course of courting, spawning or fighting.

Not sure if that answers your ?


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## jsaunsnp (Jul 14, 2008)

Bio,

Thank you for probably the the most informative answer I think I could have hoped for. I appreciate it.

As for the hardscaping, I have rock work with plenty of caves as well as calvus style rocks that they seem to enjoy. The coloring is off white and brown.

Thank you for all the informative replies.


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