# Harlequin rasbora aggression



## black_lung (Dec 19, 2006)

Has anyone else had problems with them? I added a group of five to my ten gallon, two males and three females, a month or so ago and recently one particular female has become a real hellion. She patrols out around the crypt in the center of the aquarium and will chase and nip anyone who gets anywhere near it; the other rasboras, even the cherry shrimp aren't safe. All the other tank inhabitants are terrified of her, it's not relaxing to watch. 

Over the weekend the other harlequins were engaging in spawning behavior, and she viciously attacked both sexes, I've noticed she's acting alot more aggressive since then. I thought these guys were supposed to be peaceful schooling fish?!

Do you think removing her for awhile would help? Or would another rasbora likely rise up and take her place as tank bully?


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## longhornxtreme (Feb 20, 2007)

I have 8 HR's, and I don't see any real aggressive tendencies at all... I don't know what to tell ya.


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## ranchwest (Jul 17, 2005)

I've got 18. They nip at one another slightly every once in a while, not very often at all. They're never aggressive with other fish.


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## JanS (Apr 14, 2004)

I've never experienced it with mine either, but like you said, if they're spawning it can sometimes bring out the nasty in everything....

If you have the means, it probably would be a good idea to move her out for a while. I really doubt the others would take over her position in aggression, but I could be wrong too.


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## BruceWatts (Mar 1, 2008)

A 10 gallon is a little small for HRs I would recommend at least a 20 gallon. I have never seen them be agressive other then an occasional nip with no harm done. Since she is staked out by the crypt maybe she is trying to reserve the prime breeding spot for herself.

Never seen this bahavior though.

Bruce


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## black_lung (Dec 19, 2006)

BruceWatts said:


> A 10 gallon is a little small for HRs I would recommend at least a 20 gallon. I have never seen them be agressive other then an occasional nip with no harm done. Since she is staked out by the crypt maybe she is trying to reserve the prime breeding spot for herself.
> 
> Never seen this bahavior though.
> 
> Bruce


Yeah, I was thinking the aggression might have something do to the small tank. I think I'll try removing Cybil for awhile and see if she mellows, if not, well, I'll think about that then. Sounds like I'm the only person who has seen a harlequin with a junkyard dog personality, aren't I lucky


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## apistomaster (May 24, 2008)

It is normal social group behavior of Harlequin Rasboras to post sentries at the edges of the main group.
Unless you are seeing split or ripped fins, it is very unlikely that what you are seeing is true aggression.
Have you seen any of them upside down underneath any broad leaves?
I ask because that is "spawning behavior." If they get that far along you would see eggs being laid and attached to the undersides of the leaves of Cryptocoryne plants or similar. Doesn't happen often without a heck of a lot of planning.


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## black_lung (Dec 19, 2006)

apistomaster said:


> It is normal social group behavior of Harlequin Rasboras to post sentries at the edges of the main group.
> Unless you are seeing split or ripped fins, it is very unlikely that what you are seeing is true aggression.
> Have you seen any of them upside down underneath any broad leaves?
> I ask because that is "spawning behavior." If they get that far along you would see eggs being laid and attached to the undersides of the leaves of Cryptocoryne plants or similar. Doesn't happen often without a heck of a lot of planning.


Well, for two days after I added a new cryptocoryne plant last week, two of the three females were constantly rubbing upside down underneath the leaves, and one of the males would come over and 'dance' around and in front of a particular one of them. But the oddly aggressive female would chase the trio off- the females would just boomarang back and the male followed. After the two days, I guess they gave up. No eggs were laid that I ever saw, and since then the sentry female has been watching over the new plant like a hawk. There aren't any torn fins, but one fish is kept seperated from the school from her chasing, and looks terrified.


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