Male Danio and Female Platties

[Alexis22]

I have a male long fin danio and two female platties. I was told he wouldn’t try to mate with them. We’ve had them for a week. Suddenly he seems to acting a bit aggressive towards them. Charging at them, chasing them and sniffing them a lot. Do fish have cycles? Or do they show this “macho” behavior anytime and can reproduce anytime? Just not sure why after a week now this is happening. I feel bad for these gals. 

[Theplatymaster]

@Alexis22

to start a danio is an egg scatterer, and platy is a livebearer, it is physically impossible for them to breed. Its not that you would get a hybrid fish, its impossible their breeding methods are so different.

also it looks like the danio is alone, danios definetly prefer to be in groups of 5-6+ and this behaviour could be the danio trying to figure out if the platies are other danios, or it might have decided they ARE other danios and is treating them as such.

[Rube_Goldfish]

On 2/23/2023 at 9:04 PM, Theplatymaster said:

@Alexis22

to start a danio is an egg scatterer, and platy is a livebearer, it is physically impossible for them to breed. Its not that you would get a hybrid fish, its impossible their breeding methods are so different.

also it looks like the danio is alone, danios definetly prefer to be in groups of 5-6+ and this behaviour could be the danio trying to figure out if the platies are other danios, or it might have decided they ARE other danios and is treating them as such.

I know danios are schooling fish, but are they like tiger barbs where they get more aggressive or nippy when kept individually or in too-small groups?

[Theplatymaster]

On 2/24/2023 at 12:23 PM, Rube_Goldfish said:

I know danios are schooling fish, but are they like tiger barbs where they get more aggressive or nippy when kept individually or in too-small groups?

thats a good question, if they do ive never heard of it happening.Ive always heard they are very peaceful fish..  i just think its treating the platies, like it would treat other danios, chasing them around and such. @TheSwissAquaristhave you noticed anything like this with your danios?

[TheSwissAquarist]

Nope, I’ve had them in with long-tail guppies and they’re all fine. 

[Alexis22]

I think you’re right @Theplatymaster. I went and got another danio today. Upon watching the groups at the store I noticed the same behavior. What I thought was maybe aggression or breeding activity is actually just play. They were all very much chasing eachother. I did not know danios are so active and playful. Hopefully having a friend will help my guy. I only have a 5 gallon tank so hopefully one is enough to keep him happy. Thanks for the explanation! 

[PineSong]

On 2/24/2023 at 3:15 PM, Alexis22 said:

I think you’re right @Theplatymaster. I went and got another danio today. Upon watching the groups at the store I noticed the same behavior. What I thought was maybe aggression or breeding activity is actually just play. They were all very much chasing eachother. I did not know danios are so active and playful. Hopefully having a friend will help my guy. I only have a 5 gallon tank so hopefully one is enough to keep him happy. Thanks for the explanation! 

In my experience danios are super active and can be a little frenzied ( or a lot frenzied, especially compared to platies) if they are alone. Your danio will definitely benefit from having more danios around.