# Decreasing Fish agression?



## Jeff232 (Nov 4, 2006)

I have a 100gallon planted aquarium with a few snails/shrimps/ 3 otos and 5 columbian tetras(thats all the columbians that the store had)

they are staking out territories and spending most of the day chasing each other out of their territories, they occasionally chase an oto but the typically just go and munch algae off the next available leaf.

would adding more fish to the tank reduce this agression/territorial behavior ? I wasnt really expecting to see it with tetras.


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## dyckster (Nov 28, 2006)

I haven't had columbians but my neons used to do the same thing. They ran each other ragged until I introduced a pair of killies to the tank. I'm not much for fish psychology but I think the presence of a bigger fish forced them to stick together as a school again.



> they occasionally chase an oto but the typically just go and munch algae off the next available leaf.


I love my ottos for this! From time to time someone will take a run at them and they just lumber along and perch themselves on the next available leaf. IMO they have the best fish personality.


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## JanS (Apr 14, 2004)

Yes, I agree that adding more fish would help this. Even if you increase your group of Columbians, it would help spread the aggression out.


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## Jeff232 (Nov 4, 2006)

i had heard that having a lot of cichlids for instance would decrease the territorial behaviour going on in the tank but i had never actually tried it, maybe ill put some black skirts in there as well....are gourammis peaceful fish?


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## dyckster (Nov 28, 2006)

Wow, I just realized that you said it was 100 gallongs. That's a huge amount of space for 5 tetras. I'm surprized they are able to find one another to nip at their fins.

Never had gouramis but I hear that they are the definition of peaceful fish. You should add a bunch more tetras so they start schooling. IMO they look nicer when they do that. 

Cichlids are pretty territorial but they'll probably keep the tetras in check. The kribs I have aren't too bad for aggression but I do have one big one that chases anyone who gets too close to his cave.


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## Mud Pie Mama (Jul 30, 2006)

I have found it very important to hit a certain 'critical mass' with some of the tetras for their group dynamics to work really well. I think 5 often is just not enough of one species. Try for at least 8, or 9 ... better yet 12! It would be great if you could get a few more. If you find out who orders the fish at your LFS, they can often get in what you're seeking. 

I had Diamond tetras and they were so skittish when I just had six, I increased the shoal to nine....and Bingo! Zippety-Do-Da! I had happy fish. Playful and great interactions.

I've also seen fish act strangely for the first one to two weeks they're in a new tank, it can take longer than we imagine for them to settle in and feel at home.


I really like the blue and red on the Columbian Tetra, it would be so cool to have a tank large enough for a dozen. If I didn't have the Congo Tetras as the Top Dogs in my 75g I think I'd be very tempted by the Columbians. There is just something majestic about blue colors in fish! Why is that?


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## Jeff232 (Nov 4, 2006)

Asking my LFS to get more columbians never occured to me. Ill call him tomorrow. 

A dozen or so would look nice and I really like the blue on them as well, I have always liked silver dollars and red hooks for some reason, and these columbians looked similar, i bought them so my plants woldnt be eaten away(they do nibble) as I have heard would happen if i bought silver dollars.


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## standoyo (Aug 25, 2005)

What? 5 tetras in a hundred gallons? Haha! i have like X20.

If you like silver dollars that means you like it when they are small and busy schoolers as I once did.[before planted]

How about Inlecypris auropurpureus? This fella is from Myanmar. Active schooler...


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## stepheus (Jun 13, 2006)

I would suggest just adding more of Columbian tetras. I use to have them in a really big shoal and loved them to bits.. and yes, there is absolutely no doubt that it ll reduce aggression by adding more fish. Read about it and experienced it myself =) 

However, if you increase the number of similar/identical species be sure diseases are in check. Higher the number, the higher the chance of one of them contracting a disease the whole shoal is prone to. :tinfoil3:


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## Jeff232 (Nov 4, 2006)

I now own 21 columbian tetras, and the fish are acting MUCH less territorial. As a matter of fact; what was once the largest meanest one of the bunch is now hanging out with all of the little ones(all the new ones are small). Im amazed at how fast fish adapt to my tank with all of the plants, In the past new fish appeared stressed for sometimes a day or two when first put in my tank, but now they just color up and start looking for food after few minutes.

Another positive is that my Oto's seem much more active since the new neighbors moved in.

Oto's wont eat themselves to death will they? They have quite the appetite for algae.


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## dyckster (Nov 28, 2006)

> Oto's wont eat themselves to death will they? They have quite the appetite for algae.


lol It sure seems like they will, eh? Sometimes when I spot my ottos they have little pot bellies from eating so much algae.


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## Mud Pie Mama (Jul 30, 2006)

Jeff232 said:


> I now own 21 columbian tetras, and the fish are acting MUCH less territorial.


Excellent! So glad to hear you were able to find them some buddies. I think this is one of the best thing about having a good size tank: the space available to have a large size shoal so you can observe more natural group dynamics and interactions.

I'm really looking forward to when you can post some photos?!?!!


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## Jeff232 (Nov 4, 2006)

I just took some pictures with my cheapie walmart disposable and ill have walmart put em on cd. Then ill figure out how to post a pic.


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