Aggressive new platy mother!? Is this normal?

[mamacita92]

Hi all,

First time fish owner… we have 3 female platys purchased about 6 weeks ago from Pets at Home for my child. The fish have been doing great, one was growing significantly quicker thank the others and a few days ago I found babies in my tank. Only 8 have survived/ were found but I guessing there were a lot more. I called the store and they said remove them until I could get a nursery net, which I now have. Since we only have 3 fish we don’t have a massive tank. I think it is 25l but now we have the net the space is more limited. I will be rehoming the babies when they are bigger or the tank will be over crowded.

My issue is, the ‘new mum’ has turned super aggressive and I have had to isolate her because she is attacking the other fish. I have put the babies back in a small temporary tank and she is in the normal tank in the nursery net because I didn’t want to remover her all together. I have done some reading and seen that this could be because the space is a little more limited than normal with the nursery net (I have ordered a smaller one until I rehome babies or find a bigger tank, that depends on gender of the babies I guess) or is it normal behaviour in fish that have just had fry?

I have no idea what I’m doing here, we got all females to avoid this but here we are. Apparently we purchased a pregnant fish and Pets at Home won’t help at all. They said they would take the babies and put them in the normal tank to be eaten. Well I could do that as well but it seems cruel if I can stop it.

Any advice?

 

[MattW]

Welcome to the forum

@emeraldking knows best on livebearers

I don’t know much on platys but the tank size is what I’d consider the main reason for the aggression especially since less room in now available with the net. That fish being in the net may also cause more stress on it then when not in the net. Also how much decor/plants do you have in the tank? some fish are best kept with decor/plants that block line of sight to reduce aggression I’m not 100% sure this applies to platys though

For a bigger tank I’d look on Facebook marketplace or gumtree for cheaper 2nd hand alternative if needed.

Some stores don’t segregate males and females so breeding could happen while they are for sale. I’m not 100% certain but platys may be one of the species that can store male sperm for long periods of time if males aren’t present.
As for rehoming, a Local fish store (non chain) would 90% of the time take them off your hands and put into proper care with higher chances of survival. My LFS, Abyss in Stockport has many spare tanks set up for rehoused fish if needed. I’d advise to call around any in your area if possible. Forgot to mention ask for advice at a Maidenhead aquatics if no other places can help. Most of the time their staff are very knowledgable and are experienced fish keepers

Best of luck and hopefully other members will post some better advice and tips

 

[Colin_T]

If you could post some pictures and a video of the fish behaving badly, it will offer more info.
You can upload videos to YouTube, then copy & paste the link here.
If you use a mobile phone to film the fish, hold the phone horizontally (landscape mode) so the footage fills the entire screen and you don't get black bars on either end.

If you can tell us about the aggressive behaviour in more detail it can help too if you can't post a video.

 

[mamacita92]

If you could post some pictures and a video of the fish behaving badly, it will offer more info.
You can upload videos to YouTube, then copy & paste the link here.
If you use a mobile phone to film the fish, hold the phone horizontally (landscape mode) so the footage fills the entire screen and you don't get black bars on either end.

If you can tell us about the aggressive behaviour in more detail it can help too if you can't post a video.

I can described it for sure, so the larger one is chasing one of the smaller ones around the tank pretty constantly. Whenever the small one swims by it almost lunges at it and chases it off. It looks like it’s damaged its fin. It seems to kind of stalk it watching it swimming round before flying at it.

 

[mamacita92]

Welcome to the forum

@emeraldking knows best on livebearers

I don’t know much on platys but the tank size is what I’d consider the main reason for the aggression especially since less room in now available with the net. That fish being in the net may also cause more stress on it then when not in the net. Also how much decor/plants do you have in the tank? some fish are best kept with decor/plants that block line of sight to reduce aggression I’m not 100% sure this applies to platys though

For a bigger tank I’d look on Facebook marketplace or gumtree for cheaper 2nd hand alternative if needed.

Some stores don’t segregate males and females so breeding could happen while they are for sale. I’m not 100% certain but platys may be one of the species that can store male sperm for long periods of time if males aren’t present.
As for rehoming, a Local fish store (non chain) would 90% of the time take them off your hands and put into proper care with higher chances of survival. My LFS, Abyss in Stockport has many spare tanks set up for rehoused fish if needed. I’d advise to call around any in your area if possible. Forgot to mention ask for advice at a Maidenhead aquatics if no other places can help. Most of the time their staff are very knowledgable and are experienced fish keepers

Best of luck and hopefully other members will post some better advice and tips

Yes, I’m thinking it might be the space that’s causing it because I haven’t noticed it before. However the fish is double the size of my others so I’m wondering if it’s a greedy gal.

I have a much smaller nursery net coming today, the babies are teeny so they will be ok for a small amount of time in there. I will see if that makes a difference to the fishes anger. I might need a bigger tank with the babies but i wont be keeping any males so ideally i would sex them before I buy it purely because I don’t know how many I will have

They do have lots of plants and rock type things but I did have to remove a couple for the net. Do we just think I’ve thrown the balance off and she’s annoyed I will resolve it when the new net is here!

 

[Colin_T]

I can described it for sure, so the larger one is chasing one of the smaller ones around the tank pretty constantly. Whenever the small one swims by it almost lunges at it and chases it off. It looks like it’s damaged its fin. It seems to kind of stalk it watching it swimming round before flying at it.

Are they definitely females?
If yes, then it's a pecking order issue and the big one hates the smaller one. You need to get rid of one of them if they don't settle down after a week.

If they are males, then it's a dominance thing and the big male wants the smaller one gone from his territory. Photos would allow us to check their sexes.

 

[mamacita92]

Are they definitely females?
If yes, then it's a pecking order issue and the big one hates the smaller one. You need to get rid of one of them if they don't settle down after a week.

If they are males, then it's a dominance thing and the big male wants the smaller one gone from his territory. Photos would allow us to check their sexes.

They are 100% female. I have had them sexed. I can’t really get a photo with the current set up. But all 3 have a fanned anal fin not a pointed.

 

[emeraldking]

Basically of what could be the reason for this behavior has already been given by Colin...