Why Is My Male Swordtail Platy So Aggressive?

[Alistriwen]

I am trying to figure out why my male swordtail platy (yes, it's a swordtail platy, genetically the two fish are almost identical, and they interbreed) has suddenly become our tank bully. We have a 30 gallon tank that started off relatively sparse with just some bogwood, slate, a fake plant, some java moss, 4 rosy barbs and 3 swordtail platies (2 female, 1 male.) Our 2 female swords were both moved out 1.5 - 2 weeks ago to birth in a 10 gallon tank. Both died after birthing when we moved them to a quarantine tank for unknown reasons so we bought 2 new swords as well as a regular platy female and stuck them in our tank. We also added some plants. We noticed that since we added the new fish though our male sword has begun to aggressively chase off our barbs and the platy and even his own kind to a lesser extent. The fish seem fine, but our barbs, especially the two males appear to have bits of fin missing from the attacks. We wanted to know what might be making our male so aggressive? Is he just really eager to breed with the new females or is it just too much of a shock with all the new plants and fish? This has been going on for days now and we'd like it to end peacefully

 

[mcdanielnc89]

hmmm.. Unfortunately.. I don't have an exact answer but it could possibly be that he is very stressed from the new fish? and maybe all the new things in the aquarium.. let's see what the other members think...

Reason for edit: Spelling

 

[theotheragentm]

If your fish is being that aggressive, removing it may be the only answer. Do you have a picture of that fish? I'd love to see pictures of the cross. I've never seen one. It's generally pretty hard to get a cross.

 

[poopsydrew]

Just so I have this straight first....You have 3 swordtails now, 2 females and a male and the male is being aggressive. You also have 4 rosy barbs.
First thought that would come to my mind is are you sure its the male swordtail nipping the barbs? Sometimes barbs can be nippy with one another especially when kept in groups under 6. If you have witnessed the swordtail nipping them then you have an aggressive male swordtail. Male swordtails are know to be agrressive, usually towards other males of the same species but do a search and you will find some other threds with devil swordtails.
It might be helpful to take him out of the tank for a bit and switch around all of the decorations and make the tank look different. Then put him back in. This technique helps with certain territorial/aggressive species and will make the swordtail feel like he is in their territory now.
If that doesnt work you might want to consider rehoming the swordtail or your other fish.

Hope that helps,

Drew

 

[Alistriwen]

As requested I am posting some pictures. Unfortunately they are quite poor in quality as I am only just learning how to take aquarium pics. Believe it or not, these are my best tank shots yet lol!

poopsydrew: I am not sure that it is not my Rosy barbs doing the damage to one another but I have reason to believe that is not the case. First and foremost, I have seen the sword chasing other fish around and nipping them, so I know he's at least trying. Second, my Rosy Barbs were initially the aggressors in the tank but once they settled pretty much kept to themselves. The two males try and spawn with each other when the females are off foraging and it can get pretty violent at times lol, but before I started seeing the sword going crazy I didn't notice any fin damage. I will definetely try removing him, although I wonder if being the solitary sword in the 30 gal might not be what made him all protective of his females when we introduced them again. Right now we are just waiting on some new tanks to cycle and then I will give it a go.

This is the male sword, caught sleeping. The pic doesnt do him any justice, he looks totally black in the pic when really he is black with a white belly and mouth and reflects blue, also has amazing finnage.

This is one of his female companions, another poor picture .

This is their home, even this pic came out bad somehow .

These are pics of the fry from our first two females in the 10 gallon where they are housed.

The first pic is my favorite fry, he is solid black, even his fins, medium sized compared to his siblings, but looks more like a platy fry than most of the others which I think look more sword-ish. I know 'he' might be a she but I kinda hope not as we want to keep a few to breed selectively and there'd be no inbreeding if I bred him with one of my current adults.

These are some more of the fry, more typical of the brood, mostly black with white mouths and bellies, of course to you they will look like black lines on my camera lens!

These are pics of the 30g tank my roommate took when we first set it up with the 7 fish. The male was a friendly fish then.

I noticed that the swords are actually much clearer in these pics if not as close up so you can have a better look.