Aggressive Platy Behavior?

Hey guys,

I was wondering what I should do about some recent aggressive behavior I saw coming from one of my platies.

I have 3 platies that get along great with each other. They will occasionally swim together and playfully chase each other (no nipping or pursuing). I originally had my 2 platies in my 20 gallon by themselves before I introduced my third platy. Within the same day, they were all swimming and eating together. I did notice that one of my platies (the biggest one, Sunny) would very occasionally peck at the platy she has been living with this whole time (Blue) when theres food around. Blue is super quick though, and is able avoid her and find food elsewhere until everyone is full and happy again.

I decided to buy a betta named Sushi a little over a week ago. Sushi was quite timid at first. He would avoid every fish, swimming out of their way as soon as they got close and would keep to himself. He would hide in his caves and would eat very little for a couple of days. After he adjusted, he started to become more playful and swim with my platies (almost never flaring at them and never chased them or pecked them). However, I think now that Sushi is very confident and present in the tank, Sunny is more apt to pick on him. For the first time today I saw Sunny chase Sushi and nip at his fins during dinner. I was completely shocked as they were getting along for days before this. I don’t know if this is why, but I have tried to decrease the amount I’m feeding the platies (I noticed they were getting bloated and were constipated). I don’t know if Sunny is reacting aggressively because I’ve been feeding Sushi more than her (I’ve been trying to fast the platies as well) or if she’s feeling territorial. I don’t understand why she would be acting territorial now though, seeing that its a 20 gallon tank with decorations and only 4 small fish. Regardless, I put Sunny in a breeders box inside my tank for tonight so I can figure out what to do in the meantime.

I don’t have another tank at the moment, and I’m not sure if I have the option to get a new one any time soon. Should I just increase the amount I feed Sunny again and see how they interact, or should I leave her in the breeders box for a bit? I’ve had her for so long and she's a great fish; I don’t want to give her up. I also don’t want to give up Sushi either, though. The other platies totally get along with my betta.. its just Sunny that's being aggressive. As of now I’ve only witnessed this one incident of fin nipping, but I don’t want to put any of my fish at risk. Any advice or thoughts?

Thanks as always!

 

Are you sure that your platy isn't pregnant? Some livebearers can be aggressive when pregnant. If you're 100% sure that there are 2 females and 1 male, pregnancy is the only thing that comes to mind. If it's not pregnant then it was probably just a one time thing. If fin nipping is a recurring issue, then it's probably pregnant. Also, I think putting it in the breeder box would be overkill, especially because you said that you've only witnessed one incident. Only use the breeder box if it keeps happening.

 

I guess you were right! I noticed a baby fry when I was cleaning my tank today. I don't know how thats even possible, but everyone is getting along now and I'm gonna try to raise the baby to the best of my ability. That's so crazy, I had no idea! Thanks for your input

 

If you want to keep the fry alive I recommend keeping them in a separate tank or breeder box for around a month or when you think that it's big enough for the fish not to eat it. Livebearers are notorious for eating their own fry. Anyways, glad I could help.

 

If you want to keep the fry alive I recommend keeping them in a separate tank or breeder box for around a month or when you think that it's big enough for the fish not to eat it. Livebearers are notorious for eating their own fry. Anyways, glad I could help.

Thank you! I'm keeping one of the fry that I found in a breeder's box haha. I haven't found any other babies.. but I'll keep an eye out!