Columbian Tetras causing issues

[Karacticus]

Last weekend, I bought a shoal of 10 Columbian Tetras - one of the fish I had always planned to get as they look amazing and are pretty active. The issue is that there are one or two of them that are bullying every other tetra in sight. They literally chase them into cover, so they spend most of the day hiding - including the non-dominant Columbians - which kind of defeats the point of having fish. Maidenhead are happy to have then back, but have suggested things might settle down.

Does anyone have similar experience of such fish? Will they chill out eventually?

They only bother the tetra species and leave everything else alone.

My tank is heavily planted and is about 300l. Photo attached - almost devoid of fish! I have 12 Black Neons, 4 Cardinals plus other fish that are left alone like SAE and Apistos.

I do appreciate that my next issue will be catching them! Planning the bottle trap method.

Thanks!

Mark

 

[Karacticus]

Or MHA also suggested more might make things better? Which sounds risky to me.

 

[Conort2]

Or MHA also suggested more might make things better? Which sounds risky to me.

This is what I’d suggest too if you were to keep them.

I find most of my male tetras can be pretty territorial when they want to be. A large group should at least keep the ‘aggression’ amongst their own kind hopefully.

 

[mort]

I've kept them a few times and have them as boisterous but not massively aggressive, more akin to barbs than tetra. I've certainly not had them chasing other fish species but they can certainly intimidate them and they do squabble amongst themselves.
Whilst normally it's a case of the more the merrier, I think you have a decent group already and I would suggest the other Columbians will begin to get bolder and come out more but I don't think things will improve a great deal for the other small tetras. I like these tetras with other larger tankmates or things that can stick up for themselves. If you want quieter species then I would consider returning them and swap them for something that is less boisterous like rosy, bentosi or phantom tetras (if you want something that's disc shaped) or perhaps Moenkhausia costea, which seem a nice peaceful shoaler.

 

[Karacticus]

Okay, great. Thanks for the advice. Think I'll attempt to swap them out for something else!

 

[ScareCrow]

Melanotaenia praecox might be a good alternative, similar size and colour but peaceful. Lovely tank by the way.

 

[Karacticus]

Melanotaenia praecox might be a good alternative, similar size and colour but peaceful. Lovely tank by the way.

Thanks, ScareCrow! They are lovely looking fish!

 

[seedoubleyou]

Have to agree with the option of adding more, this generally helps in dispersing aggression or at the very least spreads it out across more fish which in turn causes less stress.

 

[Karacticus]

Have to agree with the option of adding more, this generally helps in dispersing aggression or at the very least spreads it out across more fish which in turn causes less stress.

I think this might be my plan B. I guess my concern is how many more I'd need to get to level things out. I've got quite a few fish in there at the moment and still have moments where I can't see any of them! 😅

I quite like the Diamond Tetra as a possible replacement, but these might be similar.

Thanks everyone for the comments.

 

[LightingBamboozled]

Diamond tetras are generally peaceful but (and take this with a pinch of salt because it's based on a single tank with a varying sized group of tetra) always keep them in odd numbered groups. They never seemed to sort out the pecking order with even numbers up to 12, peaceful lttle school in odd numbers, even down to just 5 of them.

 

[PARAGUAY]

The tank is very well planted so breaking the "line of sight" should not be an issue but some twiggy wood were the smaller fish can retreat might be worth a try, or try something more fearless like Silver Tips . Still got your small tetras but they are a lot more active in the presence of larger fish than say Black Neons

 

[Karacticus]

Thanks. I have tried catching them this morning with zero success, so looks like they're staying for now. Will have a think on it, but not sure I want to increase the number.

 

[Conort2]

I think both silver tips or diamonds will be the same if not worse. This behaviour isn’t uncommon in tetras. My tiny little male hyphessobrycon negodagua who is no bigger than a cardinal tetra used to round up all the fish in my five foot tank when he was in the mood to spawn.

 

[mort]

The biggest issue with increasing the number is that in time, perhaps a few years, they will begin to dwindle again and you reach a point where you either add more or have to rehome old fish. I like the Columbian tetras but found with the group my brother had, that they get big and lazy as they age but are still like mini piranhas, when the food goes in.

 

[Karacticus]

Yeah, think I'm going to monitor for now. They do go nuts at feeding time! Big and lazy I can handle, so hopefully they mellow a bit. At the moment, they are tending to sit in territories and drive off any visitors. Well, two of them are assholes as far as I can see.