Aggressive Danios??

[CandiBug2]

My sister has a 30 gallon freshwater tank at her apartment. In it she has 4 Zebra Danios. I'm not sure why she picked 4 but anyway... those are the only fish in her tank. Is it normal for these fish to be aggressive? Out of the 4 one imparticular seems to be quite a bully. It chases the other fish around the tank and apparantly nips at them. When my sister told me, I had to see for myself. Sure enough, this one fish is kinda nasty to the others. Maybe we are misinterpreting what is going on, but we are both concerned. We don't want any of the other 3 to get hurt. Out of the 4, the bully is only slightly larger and by this I mean maybe a millimeter if at all. Does this matter? What is going on here?

[gregg604]

My Danios are quite playful. They chase each other all day. Is there any fin damage? If that is the case maybe try feeding them more, they might just be hungry.

On another note, my sister got a 5 gallon with 3 danios and a betta. She woke up and saw a big fight between the danios and the betta. Betta was getting nipped from all angles. since then she has moves the betta to another bowl. Danios are supposed to be frienfdly, they might just go a little crazy sometimes. I think her Ph was high as well.

[CandiBug2]

It doesn't appear as if anyone has been harmed. We were just concerned because it's one Danios doing all the chasing. The others seem content to just hang out and swim merrily around the tank.

[anonapersona]

If no damage is done, forget about it. One of the fish has elected himself boss of all the other ones, and he is trying to get them all to do what he wants, sort of like herding fish....

[Cearbhaill]

It doesn't appear as if anyone has been harmed. We were just concerned because it's one Danios doing all the chasing. The others seem content to just hang out and swim merrily around the tank.
And that's why I don't keep danios!
They can be hyper as all get out and it makes me nuts.
"Serenity Now"

[SnakeIce]

males are teritorial to other males and are always trying to get the females in the mood if you know what I mean:D
I had a male that killed adult female guppies cause he thought they should have fry for him to eat NOW lol that male had a long list of "crimes" he bullied tetras (they had eggs when someone else hit them up why not he?)
a pair of angelfish and their spawn probably wouldn't be safe with him around

if you just want a comunity and want a zippy fish, then there you go, but if you are trying to breed other fish no way am I going to have danios. they breed worse than rabbits and are incorigible egg eaters and fry eaters

[gregg604]

I've noticed that too about the males. Particularly, there is one who is the fattest of the bunch, who seems to take over during mealtime and chase everbody around. He is also usually always at the front of the school. Guess he is the leader.