For the most part they are peaceful but every now amd then you come across a trouble maker. Some of use have had this problem and for some it died down and for others the fish had to be removed.Alrighty so I've got the sand in and the bichirs love it! Since I was going to have everyone out of the tank, I decided it would be the perfect chance to add just one more poly to have 3...so I went to the same store and bought this other feisty teugelsi...But I woke up this morning and found that it was seriously fighting with my other teug!!! What? I thought these were friendly to one another? Also, I've seen people keep bichirs literally one on top of each other and see no fighting...Why are these two fighting with so much room? Is it because they are the same type? I'm gonna be taking my new teug back to the store at this point :/
Try changing the decor around and break up established territories. Also could just be a hierarchy thing and will die down soon