Glofish tetras

[Jrnew75]

We recently got my 7 year old daughter an aquarium and added fish last Friday. She wanted glofish tetras, which I know nothing about. We purchased five, one of which was a long fin tetra. The long fin one is very aggressive. I had assumed all five were the same species, but now I’m wondering whether that was wrong and the reason it’s aggressive is that it’s lonely. Two days in, I suggested to my daughter we might should return the aggressive one, but she had a meltdown and I relented. I’ve rearranged the plants several times. That calms him down for all of about two hours.

 

[Essjay]

Can you post photos of the fish, please. There are several species which have been turned into glofish and the problem may be that you have mixed species.

 

[Jrnew75]

The orange one is the long finned one. The others are like the red. To me, the only visual difference is the longer fins and the orange one is slightly larger.

 

[Essjay]

Yes they are the same species, they are genetically modified skirt (aka widow) tetras.

Here is a profile of these fish, which does note that can be squabbling amongst a group of them.

Gymnocorymbus ternetzi – Black Widow Tetra — Seriously Fish

www.seriouslyfish.com

 

[CassCats]

Its normal for them to squabble in a new environment for a week or so. It does settle down once they settle the hierarchy.
You got lots of tall plants which helps hide any who want a break

They will start bickering often if you change the tank around or if they don't have enough tetras around.

Honestly I'd add 1-2 more to the shoal and they will settle down in a week or so after.

Having more space helps too (skirt tetras need a 20 gallon long minimum).