Mean tetra

[Coz]

I put 5 black tetras in my tank and after 24 hrs one of then is running the others off. He is claiming one area of the tank and runs off any others that come close. Is this normal?

 

[Rivercats]

Yes it can be. It's most likely a dominant male. Depending on what exact type of tetra many are semi-aggressive. Usually a larger school works because aggression is more spread out. If it doesn't stop you can get more or return them. It's going to have to be a personal call on your part.

 

[Fishperson]

What type of tetra do you mean? Black phantom or Black skirt? If you add 2 more you can decrease aggression.

 

[Fishperson]

What size tank?