Aggressive Cherry barb

[RyanB]

Hi All,

I have just set up a new aquarium which has had fish in for around 3 weeks now. Everything so far has been totally fine except for the last few days.

1 bright red cherry barb has taken over a rockery area covering 1/3 of my tank. If any other fish go near come over then it aggressively chases them off and nips them.

Most fish are now just congregating on the other side of the tank. Any advice on what to do???? I am a complete novice at fishkeeping.

My tank has 12 zebra Tank or, 6 Black Phantom Tetras, 6 Platts and 6 Cherry barbs.

[TMaier]

I got rid of my cherry barbs for this exact same reason. And he chased the females constantly. Stressed me out whenever I looked at the tank.

[Autumnsky]

Often they get more aggressive when the water parameters are off. If you have a recent tank set up, it is likely the tank is starting cycling.

Do you know what the Ammonia, Nitrite and Nitrate?

Probably if you don't have a test kit, do a couple 40 to 50% pwc's (partial water changes)

Also Barbs will often be really active and seem to act aggressive and can be bullies. People say they have nice calm ones but often that is not the case. They also prefer larger groups of their own kind 1 male to 2 or more females.

I just learned about cycling but I already have fish. What now?! - Aquarium Advice

Fish-in Cycling: Step over into the dark side - Aquarium Advice

This is a good thread for learning all the basics.
Guide to Starting a Freshwater Aquarium - Aquarium Advice