Madagascar rainbow picking on zebra danios?

[trevorSB1004]

My madagascar rainbowfish is picking on my 6 zebra danios. He doesnt actually nip them, he just chases them whenever the danios cross his path. Any reason why?

 

[treemanone2003]

Possibly because the 30 is too small and it's the only one. They do best in schools and planted tanks with plenty of room to swim. May feel threatened and sounds like it's competing for space.