New Molly

I added a new molly yesterday and the molly that had already been in the tank for a few days has been chasing and startling my new molly. Is this normal and will it stop soon? If it’s harmful what should I do? I have no other tank to move either to.

 

Greetings my friend and welcome to Fishlore!
I have a few questions though;

1) What is the size of the tank?
2) What are their genders?
3) What's the décor like in the tank?

A lot of times it could be a male being territorial, females not getting along or a male harassing a female to breed with him. Fish are very....complex in a sense.

 

Mollys are mean fish! So yes its normal! They're just like that

I do agree with above though, It could be other reasons too!

 

I added a new molly yesterday and the molly that had already been in the tank for a few days has been chasing and startling my new molly. Is this normal and will it stop soon? If it’s harmful what should I do? I have no other tank to move either to.

Welcome. Aggression in Mollies is fairly common. Some are just bullies. Other times, it's two males being territorial, or two females not getting along, or a male harrassing a female. A larger tank can help.

We have a special Molly forum: Molly Forum

 

Greetings my friend and welcome to Fishlore!
I have a few questions though;

1) What is the size of the tank?
2) What are their genders?
3) What's the décor like in the tank?

A lot of times it could be a male being territorial, females not getting along or a male harassing a female to breed with him. Fish are very....complex in a sense.

The size of the tank is a 10 gallon.
They are both males.
I’ve attached an image of my tank.. I have a mountain waterfall with air stone, a live plant on log, fake plant and a pirate ship. Moderate amount of empty space in the middle.

Welcome. Aggression in Mollies is fairly common. Some are just bullies. Other times, it's two males being territorial, or two females not getting along, or a male harrassing a female. A larger tank can help.

We have a special Molly forum: Molly Forum

Oh okay, thanks for directing me towards the forum! Is the aggression harmful?

 

Okay, it's reasonable for us to come to the conclusion that your old male molly was being aggressive/territorial with the new male Molly. He's probably like "HEY YOU! This is my part of the tank, go find your own region." They'll be fine in the tank together. Although mollies aren't too too heavy on the territorial type, you could add more décor if you wanted to distinguish territories. ---> It's not necessary but optional and I'm sure that the Mollies will enjoy each other's company.

 

If they are both indeed males, I would give it a few weeks to adjust, they will size each other up, and eventually one will become the "Boss," then they'll settle down. Mollies like to argue a lot. Usually it's fine, you can turn the lights out to help settle them if they become too rambunctious with each other.

 

Okay, it's reasonable for us to come to the conclusion that your old male molly was being aggressive/territorial with the new male Molly. He's probably like "HEY YOU! This is my part of the tank, go find your own region." They'll be fine in the tank together. Although mollies aren't too too heavy on the territorial type, you could add more décor if you wanted to distinguish territories. ---> It's not necessary but optional and I'm sure that the Mollies will enjoy each other's company.

aright will some of this aggression disperse away from the one molly once i add another fish? i have two right now and i was thinking i could add another in a few days.

and thanks for all your help! this is my very first fish tank so i’m learning the ropes

If they are both indeed males, I would give it a few weeks to adjust, they will size each other up, and eventually one will become the "Boss," then they'll settle down. Mollies like to argue a lot. Usually it's fine, you can turn the lights out to help settle them if they become too rambunctious with each other.

okay, thanks for all the help

 

aright will some of this aggression disperse away from the one molly once i add another fish? i have two right now and i was thinking i could add another in a few days.

and thanks for all your help! this is my very first fish tank so i’m learning the ropes


okay, thanks for all the help

When you add the new fish, are you going to add another male? Whether it's an All male tank or All female or mixed, they will still bicker. I have an ALL female+fry 20g Molly tank right now & the bigger ones pick at each other and the younger/smaller fish - even the tiny fry argue!! Haha

 

When you add the new fish, are you going to add another male? Whether it's an All male tank or All female or mixed, they will still bicker. I have an ALL female+fry 20g Molly tank right now & the bigger ones pick at each other and the younger/smaller fish - even the tiny fry argue!! Haha

I was planning on adding another male.. I dont want any babies haha.
And that’s good to know. The molly is pacing and glass surfing.. should go away once it adjusts?

 

I was planning on adding another male.. I dont want any babies haha.
And that’s good to know. The molly is pacing and glass surfing.. should go away once it adjusts?

Good idea! Having an all male tank can be very cool! With Mollies I find the males to be more colorful than females. & the never ending fry that females create can be stressful on us humans.
About the glass surfing, I've only experienced that when I was doing in-Fish cycling of the tank or the fish was stressed out.
Do you have testing strips? Is the tank cycled? And are the parameters stable?

 

I have testing strips which I’ve been using frequently. The water parameters are stable. My first molly did this his first two days and has seemed to have stopped now so i’m hoping the new molly will adjust as well.

 

I have testing strips which I’ve been using frequently. The water parameters are stable. My first molly did this his first two days and has seemed to have stopped now so i’m hoping the new molly will adjust as well.

Okay, if parameters are all good, then he may simply be adjusting. Last year I had a female do it for 3 days before she dropped fry. So it seems to be a common behavior when they are stressed. I would just keep an eye on them, otherwise you seem to be doing great! Mollies are a great fish!

 

thanks so much!