# Aggression



## Colubrid (May 9, 2016)

I wasn't sure whether to post this in the central or south American Discussion.

I have a juvenile 1" jack dempsey in a 40 gallon breeder, had him for a while now. I thought he was kind of lonely so I decided to get him a "friend". What a mistake that was.

I was at the local petstore today when I just fell in love with this about 2-3" green terror..and I ended up bringing him home.

You might be thinking that the aggression would be in the bigger fish. Nope. My dempsey won't even let the poor thing rest. He chases him all over the place. I am in need of some advice to what I should do to solve this. This whole thing seems like a territorial issue but I'm not really sure what to do about it. I don't want to rehome the green terror either since I think he's a handsome little guy.

I am aware that a 40 gallon breeder is too small. I've already planned to move them into a larger tank when they get older.


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## BC in SK (Aug 11, 2012)

There are 2 issues here. 
The first issue is a problem of introduction. Your JD owns the entire tank to himself/herself. The GT is an intruder that is not getting the chance to establish itself. Sometimes it's necessary to remove one or more fish temporarily, re-arrange decor and/or introduce more then one fish at a time. And that is in a community tank with numerous fish. When it's a single fish in the tank, problems of introduction are amplified.
The second issue is the numbers required in order to make a functioning community tank. Only 2 cichlids is generally an unworkable number. Very seldom does it work out well and the more aggressive the species, the less likely such low numbers is going to turn out well. Often, the dominant fish will go on a seek and destroy mission ....if there is only one other cichlid, then it's competition can be easily eliminated. IMO, generally 5-6 cichlids is about the minimum in order to have decent chance of ending up with a functioning community of cichlids. Sure, there are always a few exceptions, where instances of low numbers works out.....but generally starting out with very few stacks the odds against you. 
Starting out with only a 40 gal., and depending on how soon and what size your upgrade is, will limit your options considerably.


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## Colubrid (May 9, 2016)

Ah, I'm very sorry I also forgot to include that I also have 6 giant danios in the tank.

And the dempsey seems to have calmed down. He still chases the terror around but not long. He's gotten better compared to yesterday.

I plan on moving in about a month or two, I can't really afford a new tank *yet* but I plan on doing it when they hit the 4-5" mark. I don't mind getting more cichlids if necessary. Except, I would need to know what types would be compatible with these two guys.


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## BC in SK (Aug 11, 2012)

Colubrid said:


> Ah, I'm very sorry I also forgot to include that I also have 6 giant danios in the tank.


In terms of numbers, so called schooling dithers will not count. Does not change the number of cichlids. Fish like giant danios can be sort of bodies in the way, but aren't even really part of the pecking order as they are not really seen as competition. As long as they have a place to swim and stay out of the way, I think giant danios have at least decent chance of doing OK. Though a fish like JD could eventually swallow a giant danio. I've lost most of mine to predation as cichlids such as salvini have swallowed them whole and also lost a few to cichlid aggression! Of the 26 I have purchased over the last 4 years....... I'm down to only 7, all purchased less then 2 years ago. I'm calling it 'success' as they have definitely done better with cichlids then any other small schooling dither, though for example, if I had purchased 26 blue gouramis and were down to only 7, I wouldn't be calling that 'success' at all :lol: Some other non-cichlids such as red-tail shark, blue/gold/opaline gourami often do fine with aggressive cichlids. They will count as part of the pecking order, though really not quite the same or as much as another cichlid.


Colubrid said:


> And the dempsey seems to have calmed down. He still chases the terror around but not long. He's gotten better compared to yesterday.


That's good. Once your past the hump of introduction, generally don't expect to have too much aggression problems with young juvies.
Of course tanks can change quickly and always go through many phases. As the fish grow and develop, it still stands. that having only just 2 cichlids in the tank gives you poor odds for success.


Colubrid said:


> I plan on moving in about a month or two, I can't really afford a new tank *yet* but I plan on doing it when they hit the 4-5" mark. I don't mind getting more cichlids if necessary. Except, I would need to know what types would be compatible with these two guys.


It's a tough question to answer with out knowing a time line for a larger tank, or even what size the upgrade will be. In the short term, I still think you would be better off adding a few firemouths and/or convicts or possibly other smaller growing cichlid.


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## Colubrid (May 9, 2016)

I think I'll go with a convict and see how it turns out. I've never kept a convict but I've heard mostly positive things about them


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## Colubrid (May 9, 2016)

Well shucks, that dempsey's back at it again. It's amazing how their moods swing so quickly. He was peaceful only a few hours ago and now he's suddenly aggressive to the terror. I tried moving some of the rocks around but it didn't seem to really do much.


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## Granamyr (Dec 16, 2015)

If you have a separate tank you can move him to for a day or two that would certainly reset what he thinks his territory is in the tank. If you don't have a separate tank, get a breeder box, he's still pretty small and you could put him in that for a day and then let him back out to see if that changes his attitude


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## Colubrid (May 9, 2016)

Thank you, I'll try that.


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## TheFishGuy (Apr 21, 2005)

Do not keep similar looking cichlids in the same tank, especially adding them one at a time! 
This is interesting as I'm giving a talk on managing aggression in a month at the Capital Cichlid Association in DC lol

I've even got a slide with a green terror and Jack Dempsey on it pointing out that they're too similar looking to house together!

Return the GT.


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## BC in SK (Aug 11, 2012)

TheFishGuy said:


> Do not keep similar looking cichlids in the same tank, especially adding them one at a time!
> This is interesting as I'm giving a talk on managing aggression in a month at the Capital Cichlid Association in DC lol
> 
> I've even got a slide with a green terror and Jack Dempsey on it pointing out that they're too similar looking to house together!
> ...


I don't buy that at all!
That a GT and JD are somehow similar looking to some people, maybe. But I sure don't think they are very similar looking at all. Different markings, different body shape, different mouth/snout, and really not even the same coloration either. Regardless of how different people will see the fish, really has little to do with how the fish will see each other. An acara is very  different from a CA cichlid. 
Fish have no problem recognizing their own species when different colored aquarium strains are housed together. No problem recognizing leucistic/albino. No problem recognizing what ever man- made color variety is developed as being the same species as themselves. Some times people don't recognize different color varieties, but the fish have no confusion because of different coloration. Maybe when it comes to mbuna, sometimes the same coloration can be a source of confusion for the fish, but then we are dealing with fish that are also very, very closely related.
Kept JD with GT a number of times together for many, many years, with no problems or really much interaction between the 2. Also known other people to do the same. Also seen a number of threads over the last 7-8 years, where people have kept the 2 species together with out issue. If it really were a case of the fish being too similar looking, then there should be some consistency to the expected aggression problems. Conspecific aggression is pretty obvious and easily recognized. In the past, I kept JD in groups, and like many CA cichlids, the conspecific aggression is very noticeable and at times can be very extreme. Nothing of this sort between GT and JD. I once had an aggression problem between a GT and an Oscar. Had to remove the GT twice until the Oscar got much, much larger and finally stood up to the GT. I guess if the 2 fish some how looked similar in my eyes, I could make the claim they shouldn't be housed together because they're too similar looking!
If there is friction between JD and GT, IMO, it's very unlikely to do with humans seeing them as somehow similar looking. There both fish of similar size and similar aggression, that could find themselves as competitors for the same position in the pecking order.
I think the OP's aggression problem has already been explained much better then the theory that a JD and GT could somehow mistake each other as the same. It's a problem of introduction. Too small of a tank. And an insufficient number of cichlids to give decent chance of it working out.


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## TheFishGuy (Apr 21, 2005)

It's not how YOU see them silly. It's how they see each other!


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## BC in SK (Aug 11, 2012)

TheFishGuy said:


> It's not how YOU see them silly. It's how they see each other!


No, it's you that are seeing the 2 fish as similar. 
If the fish really did see each other that way.....then there would be some consistency of aggression, from one tank to another. Should at least be some what similar to conspecific aggression. Yet, nothing of the sort in my tanks nor in many other aquarist's tanks.
Secondly, there is no basis to assume the fish see each other as similar because they are neither all that closely related nor are they difficult to tell apart. If people can easily see the difference, why would you think the fish couldn't tell the difference? :lol: 
I don't doubt you have had problems keeping the 2 species together..... but I really question your assumptions that the fish are seeing each other as somehow similar.


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## TheFishGuy (Apr 21, 2005)




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## Colubrid (May 9, 2016)

Well things have finally calmed down between the dempsey and the GT. I just got a convict, about the same size as the dempsey and I'm not seeing any aggression besides slight chasing. The convict really wasn't planning on getting bullied LOL! he ended up chasing the dempsey away after about only 3-4 minutes of being in the tank.

Hours have passed since the convict was introduced, and all 3 cichlids seem to mind their own business.


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## Colubrid (May 9, 2016)

Update:

My green terror just died today. He ended up getting ich out of nowhere and got some weird fungal disease. Hopefully the others don't die either..


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## Granamyr (Dec 16, 2015)

Sorry to hear that always stinks when you lose a fish


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## Colubrid (May 9, 2016)

It sure does. The outbreak quickly died down after a few days. Not much damage was done besides the loss of the terror. The convict has started picking on the dempsey, I probably need to add another cichlid.

Does anyone have any suggestions to what I should try and add? I'll probably need a more semi-aggressive cichlid that can handle the dempsey and convict.


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## Colubrid (May 9, 2016)

I ended up getting two more cichlids. A tiny firemouth and another green terror who is more aggressive than the last one that died. Which is good.


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## TheFishGuy (Apr 21, 2005)

I fear this will not end well.
Again.
But what do I know.


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## Colubrid (May 9, 2016)

It didn't go well for the little firemouth, but I did get a bigger one their size. Haven't released him into the tank yet.


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