# Why Are Guppies So Aggressive?



## Teebo (Jul 15, 2015)

I have a 5 gallon shrimp tank, that I have been trying to keep fish in. I did a lot of research into tiny fish and what would work, I brought home three male Cobra Endlers. They picked on each other and were aggressive, too active, all my shrimp hid. I removed two and left just one and he calmed right down by himself, all the shrimp came out. 

Few weeks later I decide to try and add a tiny male feeder guppy, that thing is smaller than an Endler and he went after the Cobra right off the bat. They do nothing but fight each other face to face, they both do this back arch toward one another. They never leave each other alone so I do not understand why all the aggression occurs, too small of a tank for males? I would rather get rid of the Cobra and keep the $0.15 feeder, possibly try a second male feeder...but I can not catch this Cobra Endler! lol


















I will not put Tetra in here because I do not have enough room for a school, they like company and guppies are content alone. If I could ever find them locally I would buy Chilli Rasboras for this tank assuming they are not aggressive.


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## geisterwald (Jul 18, 2016)

Usually aggression problems happen, to my knowledge and in my experience, when males are competing for a female to mate with, so if males outnumber females, basically. I don't know that I've ever heard of problems in an all-male tank but I imagine it's the same thing, battling for mating supremacy or whatever.


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## jeffkrol (Jun 5, 2013)

I have 9 male guppies in a 55gal and all they do is play in the currents..


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## geisterwald (Jul 18, 2016)

jeffkrol said:


> I have 9 male guppies in a 55gal and all they do is play in the currents..


Well that's a 55 gallon tank which is a totally different animal, 11 times the size of OP's 5 gallon. OP might just have too many males with no distractions (females) in such a small tank, resulting in territorial disputes.

Edit: whoops, I forgot you only had two fish. Still, I don't think they have anything to do but fight each other. I don't know what kind of territories guppies like to maintain, but I think this guppy is seeing the endler as competition for something.


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## Varmint (Apr 5, 2014)

This could make things worse or better. Get one more. Sometimes when there are more fish the aggression gets spread out. 

I have four that I newly added to my 12 gallon last week. All they do is play and try to hump each other.


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## Teebo (Jul 15, 2015)

I already got rid of two, so going up to 4 seems like it will not work. There are no females in with them because they get too large and I have nothing to do with the fry. I am having an extremely hard time catching my last Cobra Endler though. I could build a trap but it would be full of shrimp too.


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## roadmaster (Nov 5, 2009)

Male guppies,male gourami,male swordtail's, many of the cichlid species,a few other's, are particularly aggressive with other males.
Is a shame there is no room for three or four females for aggression among males drop's off considerably in the presence of females, assuming of course they aren't vying for the attention on a single female (hence the suggestion of more females to males). 
Is just what they do more often as not.


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## Teebo (Jul 15, 2015)

I will have to keep a single Endler or feeder and draw the line there until I can get Rasboras. There is really not much room for anything else, maybe Minnows.


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## Bad Kitty (Jun 13, 2016)

I have 2 Japanese Blue Endlers in a HEAVILY planted 5 gallon. They would "present" to each other before the plants grew out but ever since the whole back half of the tank grew out the top of the tank they have been really peaceful with each other. Whenever I put a female is the only time they compete with each other now. I also have a 10 gallon with 3 Green Cobras and 3 Flames all males and with a old betta crown tail. They are also always peaceful and do not fight unless I am breeding them. 1 of 2 things could possibly be happening.

1. If you are buying Green Cobras from Petsmart they could be violent from their handling conditions.

2. What is the parameters of your tank? Any species of Livebearer prefers hard water and a higher PH. Any extra stress (even ammonia spikes due to new fish being introduced to your bio-filter) can cause aggressive behavior in any fish. Nano tanks such as 5 Gallons can shift in water parameters very easy. adding new fish to a tank that small that has only had shrimp in it will take time to acclimate to the new load.

Just some ideas because I breed them and have never had any problems with them constantly fighting. Every once in a while sure but they generally shoal in groups of 5 or more or leave each other alone in lesser numbers and pick a side of the tank. 

If you want to catch an Endler I have better luck putting in a floating Betta pellet and wait for the Endler to come up to it. They will try to grasp it slowly and at that time scoop them from behind with a net.


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## Schoolofdisabledguppies (Jun 9, 2018)

Competition. Happens all the time in nature.

Bump: I heard if you have a lot of one fish, they would form some sort of hierarchy because the Alpha can't deal with a lot of males.


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## Ralmato (Jul 14, 2018)

I have some guppies, tetras and otoclinclus catfish (sucker fish) in my tank and all have been doing well except for a oto catfish that has passed on. One of my guppies, a male(the one with a red tail) has been really aggresive with the one with the blue tail, a female (Picture 2) the male is always chasing the female around and nipping at her tail while the female is trying to avoid him. My other fishes are fine and seem to be ignored. May I know if this is normal? 
-newbie


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## babystarz (Sep 25, 2012)

Ralmato said:


> I have some guppies, tetras and otoclinclus catfish (sucker fish) in my tank and all have been doing well except for a oto catfish that has passed on. One of my guppies, a male(the one with a red tail) has been really aggresive with the one with the blue tail, a female (Picture 2) the male is always chasing the female around and nipping at her tail while the female is trying to avoid him. My other fishes are fine and seem to be ignored. May I know if this is normal?
> -newbie


Yes this is normal, male guppies do chase the females. I would recommend you get at least one more female (or more than one) so that the male will split his attention between multiple females, allowing any that are tired of him or pregnant to get some peace. I have much better luck with housing 1 male with 2 or more females.


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