Suddenly Agressive Platy...

[edetore]

Hi! I could use some advice here as I am a novice to fish keeping...

I have a 14 gallon freshwater tank with 2 platies, two guppies, a snail, and one guppy fry (in a breeders net). I've gotten through the rough start and nitro cycle and seem to have everything going swimmingly as far as feeding, temps, and ammonia/nitrate levels. The fish up to now have also gotten along well with no issues...the platies have been together since December and the guppies were introduced in February.

However, in the last two days my male platy has been roughing up what I think are the female platy and guppies (I am guessing gender based on the bottom fins being more fanned than pointed...and the platy is black so I can't see any gravid spots). He seems to leave the other guppy be...and although I think my fry is large enough to leave the breeder net I am keeping him there until I get this aggressive behavior under control.

I can't see what may have changed in the tank to instill this hostility but he is really chewing their tail fins up and has them both, particularly the platy, in hiding rather than swimming about. For the moment I have pulled him out and put him into a small goldfish bowl until I can figure out what else to do...I am afraid he will stress the other two to death if I leave him in the tank.

Any ideas on why the sudden change and how I can reintroduce him?

 

[amy1994]

Males can be like this to the females, chase them about all day long etc, really you should have atleast 2 females to every male, even though it's better to have more. If the female platy looks bigger than normal, she is probably pregnant, but like you say it is hard to tell, i have black swordtails so i know what you mean, and unfortunatly i haved missed some.

Im gessing you also have a male and female guppy? Which could be why he leaves the other guppy alone. You should also have 2 female guppies for each male, even though it's better to have more. With the fry only let it out when you are sure it is big enough not to be eaten by the platies.

If you want to reintroduce him, to do as you would to a new fish, but it might be worth doing it a bit slower, keeping him in the bag for a little big longer. As for the sudden change.....not really to sure hopefully someone else can help you with that.

 

[OldMan47]

Welcome to the forum Edetore.
I do not tolerate extreme aggression in any of my livebearers. There is no reason to ever allow aggressive traits like that to be passed on to fry. I do not know that aggression is an inherited trait but I simply don't chance it. You have a very small tank for that many fish which may be a part of the reason for aggression. Crowding always seems to bring out the worst in our fish.