Harlequin

[razbora]

Hello. I am new to these forums. I have my harlequin mixed with a blackline rasbora and a glowlight. Now I know that generally the Harlequin is a peaceful fish, but it had been alone with no other fish for a while. Would this cause it to become over dominant? It is constantly chasing around my two fish even though the blackline is bigger than it. How can I keep the peace in my tank?

 

[mikev]

Get each species in sufficient numbers. Shoaling fish generally needs to be kept 6+ to be comfortable and feel secure.

hth

 

[Lateral Line]

Mike is right. In small groups, naturally gregarious fish will be stressed and show atypical behaviour which can run from hiding away and slowly dying all the way up to outright aggression. If your tank has the space, (overcrowding can also cause stress), you want at least 6 of each species you mention.