# Agression in fishes



## Polypterus (May 4, 2003)

I want to take a poll here, What do you believe is the cause of aggression
in fishes?

1. What do you think the most Aggressive fish is?

2. Why is that fish aggressive?

3. How do you think that fish behaves in an aquarium?

4. How does that fish behave in the wild?


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## Innes (Jan 13, 2003)

from what I have read I think the most aggressive fish is a tie as some species are so aggressive they just attack!!!
these include:
*S.elongatus
*Midas cichlid
*Flowerhorns
*Red devils

I'm sure their are others like a Dovii or however you spell it

I believe that these fish are solo species and will attack even plastic divers and nets, not to mension any fish in the tank.

Flowerhorns dont live in the wild, but can be super aggressive in an aquarium, the other cichlids I assume are more terratorial than simply pissed off so I assume in the wild with lots of space they are much more tolerant of other fish.
as for the S.elongatus, it wouldn't suprise me if in the wild they shoal, vut I would expect them to still be a bit aggressive, but more for food and not just for kicks.

I think that these cichlids are aggressive as they are terratorial - why they are like this I have no clue, and the S.elongatus is simply a killing machine, and also is terratorial to boot.

Oh, and how could I forget about snakeheads?
and Great Whites?
......

well I think I answerd your questions.


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## acestro (Jul 7, 2003)

Aggression is a strange word to define. It can include beating up tankmates or eating/fin-nipping.

This is a cool topic to discuss.

I can only guess that the most aggressive fish is perhaps a mako shark. Because of their shark eating habits and their high speed/high metabolism way of life.

Why fish act aggressive....either eating or defending a feeding or breeding territory.

A tank with a smaller area than the fish's natural territory will create a hyper-aggressive situation.


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## Polypterus (May 4, 2003)

Interesting, More people come on you are reading it contribute, add to the mix


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## mtx1 (May 21, 2003)

most agressive i have no idea my most agressive fish is my xingu rhom it will attack the syphon when i put it in there. i think the reason they are agressive is to protect themselves or territory...like a aggressive dog...we have a rottweiler and it wont let anyone near the house or car unless we hold her and show that they are ok...since we cant really interact with fish and talk to them therefore we have not much control over what they do. i think in a aquarium (like a dog at its house) it considers the aquarium its and therfore protects from intruders my rhom will kill everything i put in there no matter what it is...i can drop in 2 dozen feeders and he will eat the first and kill the rest to float on the bottom. i think in the wild that the fish would do the same to a certain area of its living area but not as aggressive as an aquarium because lots of other fish come and go in the wild unlike the aquarium where it will only see fish every other day.... just my 2 cents


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## piranha45 (Apr 8, 2003)

Polypterus said:


> I want to take a poll here, What do you believe is the cause of aggression
> in fishes?
> 
> 1. What do you think the most Aggressive fish is?
> ...


I regard your 1/2/3/4 Questions as irrelevant. I'll try for a much broader, effective answer.

I know of highly aggressive fish, but I do not know of all the fish that exist in the world so I really couldn't name a certain specie. Out of my very limited knowledge, Istlanum and Beani cichlids are the most aggressive fish.

Most, if not all "Aggressive" fish, are Territorially-Aggressive. They require territory, and if they feel their space is being violated, they will attack. Many cichlids, snakeheads, Serrasalmus piranhas, etc etc appear to act in this fashion.

Other fish are only considered "aggressive" due to Hunger. These fish will only devour anything they can fit in their mouths/easily kill. Catfish and some piranhas seem to fit this category. I would not regard this as true "Aggressiveness", however.

Aggressiveness would be more related to attacking-out-of-maliciousness, rather than to satiate hunger.


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## Polypterus (May 4, 2003)

> I regard your 1/2/3/4 Questions as irrelevant. I'll try for a much broader, effective answer.


Much better to do so, 1/2/3/4 questions are just guides for continued dialog


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## o snap its eric (Feb 19, 2003)

Polypterus said:


> I want to take a poll here, What do you believe is the cause of aggression
> in fishes?
> 
> 1. What do you think the most Aggressive fish is?
> ...


 1. no such thing as agressive. More like territorial. But i use the word agressive because no one listens to me.

2.Highly territorial

3.Aquarium does not provide enough space.

4.I would imagine just like they were in the aqurium but they have a limit in their territory and 90% of the time they only swim within their space.


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## Innes (Jan 13, 2003)

not all fish have aggression through being terratorial


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## o snap its eric (Feb 19, 2003)

Like what fish then?


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## piranha45 (Apr 8, 2003)

i think territorial could indeed be a more accurate term than aggression... altho i and everyone else was raised on the term "aggression" so i doubt im gonna alter my vocabulary at this point


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## Polypterus (May 4, 2003)

I have only noticed four instances where a fish can be
termed "Aggressive". 
1. Territorial displays
2. Feeding behavior
3. Breeding behavior/ egg and fry protection
4. Fright without a means to escape

personally I'm not all that keen
on the term aggressive at all, as this seems more to be a 
Human behavior not a fishes,


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## o snap its eric (Feb 19, 2003)

Polypterus said:


> I have only noticed four instances where a fish can be
> termed "Aggressive".
> 1. Territorial displays
> 2. Feeding behavior
> ...


 I think the word agression is used too loosly. I agree you can see "agression" when it is feeding time, and protection of fries and eggs (that can also be said territorialness). Agression is more of a human trait rather than fish. If you look hard enough, with 98% of the "agression" is always caused by territorialness. Cause and effect guys!


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## piranha45 (Apr 8, 2003)

yeah...


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## Show_Me_The_Teeth (Dec 4, 2002)

Red SH are by the most aggressive fish I have ever seen. I know I have been ramming this Red SH stuff on all the threads now but I am still in shock of what my Red can do. I have never seen anything like it. Its aggression comes from it being hungry to territory to whatever. Any fish that is willing to come out of the tank gots to be one of the most aggressive fish ever.


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## Polypterus (May 4, 2003)

Red Snakeheads are not aggressive they are stomachs with fins,

Their whole purpose is to feed, and they do it well.
Starve them they do it better.

If I was to use that as a definition 
some Lampreys are the most Aggressive fish in the world, They live to feed 
Breed and die, they by far have the biggest balls of any fish, as they
openly prey on species five times their size, they regularly feed on those 
that could easily feed on them,

"Aggression" though is not in a Lampreys nature, they are very shy fish,
and do not seek any territory, they are though The pinicale of Predatory
evolution, A parasite.

"Aggression" in fishes is a joke, in all cases this so called "bad ass atitude"
of perticular species can be linked to Biological needs,

Anthropomorphizing fishes is a falicy, it blinds you to what is the
true root cause of Behavioral interactions, To constantly dwell on what
is "Agression" truly limits your ability to really understand or know
those fishes you own, and if you truly only care to make Human
and Dream up behaviors for your ammusment, I feel sorry for you and your fish.

There is much to be learned and much to be discovered about these fish,
Dwelling on presumed "Human-like" behavior is counter-productive.
And pitting one against another is just plain Infantile and downright stupid.
Moral equivelent of a Dog fight or c*ck fight Senseless Stupidity.

Translation:
BLAH BLAH BLAH 
Blah Blah
Blah blah blah "aggression" Blah Blah Blah
Blah blah "Bad Ass Atitude" Blah Blah
Blah Bla Blob Blah Personal ammusment Blah blah bla
bla blah bla c*ck Blah blah bla blah bla.
Pissing in the wind, feeling kind of wet


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## Black Piranha (Feb 1, 2003)

1. What do you think the most Aggressive fish is? there is not most aggressive fish. they all vary. personally i think the most aggressive fish is the African Tiger Fish

2. Why is that fish aggressive? this fish is aggressive because it is a pred. most pred fish are aggressive

3. How do you think that fish behaves in an aquarium? i know how it behaves in an aquarium. very aggressive. it doesnt swim into walls and stuff. but i wouldnt put ur finger in.

4. How does that fish behave in the wild? they are predators. full grown 72" african tiger fishes are known for attacking small children bathing in rivers.


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## piranha45 (Apr 8, 2003)

Black Piranha said:


> 1. What do you think the most Aggressive fish is? there is not most aggressive fish. they all vary. personally i think the most aggressive fish is the African Tiger Fish
> 
> 2. Why is that fish aggressive? this fish is aggressive because it is a pred. most pred fish are aggressive
> 
> 3. How do you think that fish behaves in an aquarium? i know how it behaves in an aquarium. very aggressive. it doesnt swim into walls and stuff. but i wouldnt put ur finger in.


I am outraged that you would go and post about a fish specie that you are obviously SOOOOOO naive of, and THEN claim to have firsthand knowledge of said fish!









african tigerfish are a very placid, docile fish in the aquarium. Their temperamental aggression is less than even a piddly S. Nattereri piranha. They are very easily bullied/killed by damn near any territorial tankmates. They will only attack small, easily-swallowed minnows and small feeders

And yet you claim to KNOW about this fish firsthand? Jesus christ man don't go bragging about _lies_

If you had posted that content in Predfish's Other Predatory Fish forum, you would have been flamed to hell and back by now already for blathering on about something you obviously know nothing about

You came off all your speculations from a few tigerfish pics you found on the net, and said to yourself OMG TEETH :rock:

Very pathetic post on your part


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## piranha45 (Apr 8, 2003)

african tiger fish, most aggressive fish in the world..... my god

ill bet you think gars must come in 2nd :laugh:


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## Judazzz (Jan 13, 2003)

P45, if you have nothing constructive to add, please, just STFU.....









Disagreeing is fine, but you clearly crossed a line here: if you lack the tools for civil discussion, then don't participate at all....

Thank you....


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## piranha45 (Apr 8, 2003)

excuse me, did you fail to notice he's outright _lying_?


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## Judazzz (Jan 13, 2003)

So what, there's other ways to make that clear...


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## o snap its eric (Feb 19, 2003)

Lets not derail this thread now....... as we all know p45 is a bit harsh in his wording and very sarcastic. Buy anyhow, ATF are very docile fish. The word "agressive" should not be related to ATFs. True they are predatory but "agression" comes in many levels. The most common definition to hobbyist is the ability to "attack" your finger through the glass and willing to kill feeders and eat it.


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## Lahot (May 20, 2003)

while P45 said it a little over the edge, I'd ahve to agree with him on this.

as for most aggressive fish
1. Redtail Cat
2. It's hungry, very very hungry
3. All the ones I've seen in aquariums are very low key, until they decide to eat something or kick something out of it's territory.
4. No idea

I've seen at least 3 in show tanks in stores, and a buddy has had 2. His most current one ate a silver arowana, 3 tinfoil barbs, at least 1 parrot, plus a few gouramis.


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## Show_Me_The_Teeth (Dec 4, 2002)

Redtail Catfish being aggressive???

I think not...my Red Snakehead killed an 18 inch SA Redtail Catfish before I got her.


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## Lahot (May 20, 2003)

wow...your big snakehead ate a little Redtail...let's try it with a 40"er...oh wait...that's your challenge thing...go buy one and try it.

Poly> good attempt at a discussion on aggression here, but it seems a little too much for a piranha site.


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## o snap its eric (Feb 19, 2003)

Oh boy, you guys are mixing up "agression" with hunger. If a fish is hungry of course they will do anything to eat, maybe kill too. It looks like agression but its just really not. Like i said, agression is caused by many factors such as space, food, and mating. People use agression too loosly. They are clumping all the factors that charatcerize are "agression" into one word which is not true. Its time for people to understand there is a difference between killing because they are hungry and killing for joy. Catfish is hungry and predatory! Not agressive!

Agression = BS that LFS say to make sales. Oftenly misused!


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## acestro (Jul 7, 2003)

Okay, here's the 'cut to the chase';

Distinguish between predatory and agonistic aggression

Predation is obvious

Agonistic behavior includes territoriality and dominance heirarchies (example; fish keeping a "pecking order")

Kicking predation out sets up this question as a measure of agonistic behavior. So, who defends their territory best OR is the meanest in settling "who's boss" in a heirarchy. That should help (I hope! )


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## Polypterus (May 4, 2003)

I leave the Thread for five days









thanks Acestro, you bring into this a very valid
subject, Social order and heirarchy in fishes, this is
often a very overlooked subject, What have people here noticed
Within their tanks? also have you noticed obvious signs of 
avoidance behavior in typically aggressive species toward
Other aggressive species ? what type of Behaviors did those fish take?

I also am quite sick of Predation as Aggression, No more posts
will be posted on this, I will delete them, or shut this topic down,
Predation is not aggression this is nothing more than carrying out
natural functions,


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## piranha45 (Apr 8, 2003)

well regardless i think we've established that Territoriality is the cause for non-predatory aggression in all fish species out there


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