# Black Skirt Tetra Unusual Behaviour



## mkg_aquarium

I have 4 black skirt tetras which are usually pretty chilled and always swim across the tank in a group. Of late (past 3-4 days) one of the black skirt tetras has stopped schooling and is always located in one corner of the fish tank above the filter. To me it looks stressed. It never leaves it's corner. I also noticed that it's tail has some kind of red markings, unlike other tetras that are in the tank. What could he be suffering from ? 

The only thing that has happened over the past 3-4 days is that I've introduced about 10 serpae tetras. I have not noticed any fin nipping on other fishes since their introduction. The other tetras are not exhibiting any odd behavior and mingle in between them. But this guy seems to be having some problem. Please Help !!

Lonely Tetra - Always floating in the corner over the air filter



The other tetras seem to be doing just fine...



Unusual red marks on the tail of this tetra - not observed on other black skirt tetras...


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## woody019

Could possibly have something to do with its sex, the least dominant male. Or could be the runt meaning the lowest on the totem pole for a lack of better words. With schooling fish it tends to be better to get the largest number you can support that way when on gets picked on it can take its aggression out on another....so on and so forth. Or could be fighting an infection and the other are picking on it while its weak, which not uncommon.

Thats just an educated guess on schooling fish behavior though.


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## Buerkletucson

I've had Black Skirt Tetras (Black Tetra, High-Fin Black tetra, Black Widow) in my tanks for over 35 years.........

Can't see your whole tank but it doesn't look like you have any hiding spots?
Even "Schooling" fish have a sort of pecking order and will sometimes pick on a certain fish in the school. 
Without a place for temporary refuge he will suffer and become stressed, sometimes resulting in death. 

How long have you had the 4-Black Tetra's?

To me, it just looks like he's getting picked on and needs a place to hang out for a bit.


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## MriGuy85

My tetras do the same, pick on each other. They don't always school together either. Some like to swim off on their own. I have lots of plants in my tank for them to hide in and everyone seems happy. Get some hiding spots. 

Since nobody has asked yet and you didn't say, what are your water parameters? How old is the tank?
Also, tank temp? Maybe he's struggling for oxygen? Higher tank temps mean less overall oxygen.


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## Arthur7

The tail fin of this fish does not look good.
The others will have bitten him. Now it ignites. It can be fin rot when germs are in the water. Separating, until healed, would be good


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## bolram

Remember serpae tetras can be very active and excitable fish where as the black skirts can tend to be more docile in comparison (even though they can be just as bad) so the new additions can cause a bit of stress on your previous fish with new additions that are extremely crazy to what they are used to. 

It seems he has tried to find the quietest and usually dimmest place possible to hide out in. Although the tail does look slightly out of shape, can you see any noticeable fraying around the fin edges, even if only slightly?


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## mkg_aquarium

Buerkletucson said:


> I've had Black Skirt Tetras (Black Tetra, High-Fin Black tetra, Black Widow) in my tanks for over 35 years.........
> 
> Can't see your whole tank but it doesn't look like you have any hiding spots?
> Even "Schooling" fish have a sort of pecking order and will sometimes pick on a certain fish in the school.
> Without a place for temporary refuge he will suffer and become stressed, sometimes resulting in death.
> 
> How long have you had the 4-Black Tetra's?
> 
> To me, it just looks like he's getting picked on and needs a place to hang out for a bit.


I am new to aquariums...I am having this fish tank since October 2013. These tetras were given to me by the guy who sold me the tank along with the first batch of fishes. I don't know their age, but 2 seem to be still small and 2 seem to be mature.

I actually took this one out. I was out a couple days and when I returned this fish had one of its eyes missing...couldn't stand it. Besides I thought maybe was afflicted with some disease...

Anyways, one of my other tetras seems to be in trouble. In your experience with tetras, have you come across this ?

http://www.aquariumforum.com/f5/embedded-black-bits-widow-tetra-video-78305.html

Please help !


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## MriGuy85

Give us your wanted parameters. Can't help if you don't give the requested info.


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