Tetra aggression

[Alice B]

for a while there all was happy in my 40 long, with 5 Buenos Aires Tetras and 1 Columbian. That Columbian has muscled up, the 2 largest BA tetras are dead and of the 3 remaining, the new target has been chosen. Only other fish in the tank is a small Albino Bristle nose. . I have quit buying fish until I set up some kind of quarantine tank, I have in surplus fish some guppies. and some corydoras catfish. I don't consider my trilineatus cories surplus. I could put some guppies in, or I could move the columbian to my hex tank with a couple of plain male guppies and a couple of ABN (daddy and 1 or 2 babies - tons of cover in there), or I can ask for suggestions preferably that do not involve buying fish. Help

 

[Byron]

Unfortunately this was inevitable. Tetras are shoaling/schooling fish, and that means they absolutely must have a group. Six is/was the often-cited number, but we now know that is not sufficient. I would aim for 10 of any of these species. In smaller groups, the fish show increased aggression; normally aggressive species become much more so, and normally peaceful species become aggressive. It is usually to others of their own initially, but it will spread to any other fish in the tank that thy take a dislike too. I've seen it in my own tanks when through old age a shoaling species is down to three or four. But we have scientific studies proving it.

In your situation, the Columbian was alone, and eventually this took its toll. And he naturally went after the only other upper fish. I have never heard of this reversing, so the answer is not acquiring more Columbians, that cold be even worse. This species, which is Hyphessobrycon columbianus, has a reputation as something of a fin nipper at the best of times, and it is boisterous and active. Which is not so bad in a group of 10+.

Guppies might not be advisable with either tetra, given the fin nipping.

The same would have occurred in time with the five Buenos Aires Tetra (Hyphessobrycon anisitsi), they too need a group around 10=plus. Either species would be OK in a 40g as it is 36 inches (or longer?) length. I personally would not keep them together, given their very similar behaviours.

 

[10 Tanks]

Hello Alice. Buenos Aires Tetras are naturally aggressive as are most of the larger Tetra species. I have 40 or so in several tanks, but not in a tank as small as 40 gallons. The smallest for my BAs is 52 gallons. 55 gallons seems about the best. Those tanks are 48 inches long. Eight BAs is the minimum and 12 is optimum. With Tetra species, more is always better.

10 Tanks (Now 11)

 

[Alice B]

I can take the 3 Buenos Aires to join a group of 10+ in a 100 gallon on Monday probably. That just leaves me with a columbian. My 40 gallon is 48 inches long, 13 wide, but only about 14 tall. I don't think I will be buying any more tetras. After my run with neon tetra disease, I don't trust fish stores to sell healthy ones. These came from an individual when a tank was sold and I took a dozen to the 100 gallon and kept 6 fish here, thinking maybe they would breed in a almost single species tank. It just did not work out

 

[powerdyne6]

My Penguin Tetras when I had 5 of them a while back were a little aggressive to each other and there was a clear aggressor.

Once I added some more to my tank (13 of them) the aggressive behaviour completely stopped.

 

[Alice B]

But I can't get healthy tetras in North Texas. I can't get healthy fish, I am slowly backing out of the hobby I think. I think I will advertise locally and see if I can find a home for the columbian. I posted him in a fish exchange, to see if anyone else has a school. He's perfectly healthy. If I can get all the tetras out I can give the tank to my trilineatus corydoras. There is a sand end for them, it's very clean, couple of sponge filters plus an undergravel.

 

[Alice B]

note: when I got these I did try to find more columbian tetras in the shop that had the healthiest stock and he didn't have any.

 

[Byron]

These things happen, unfortunately. Either we cannot get sufficient numbers, or they are possibly diseased. The lone Columbian may be a real nasty fellow by now, but there is always the chance that placed in a totally new environment with the large group he may fit in. But it won't be your problem, and there really is no other option in his favour.

 

[Alice B]

if no one takes him I have 4 ponds. My first choice is adoption. I don't think he's going to bully fish as large as my goldfish. The koi would probably eat him

 

[Alice B]

I have a lady picking him up in 24 minutes, getting him in a bag

 

[Alice B]

and he's gone, going to check out the killifish forum. I can drop the BA tetras off into a large school on Monday. I just saw raising my own live food. With my schedule, I think I am going to move some of the guppies into the 40 gallon for now. I may not have time to look at all the info on killifish.