Platy is killing my Guppies!

[bunyshaven]

First time posting, read through the forums and didn't see an answer, so I thought i'd ask.

We have a 10 gallon tank, with 2 blue platys, 2 sunset mollys, and just added two male guppies. Water levels are fine, we got them tested at 2 different stores. PH is fine, and we just did a water change yesterday.

The problem is, the larger platy (more round, bigger belly, I can't tell if it's a female) is harassing the guppies. This mean fish is RELENTLESS. We don't have another tank to put him in, but he's non-stop nipping at the guppies. Parts of their tail are missing and the orange one is about to die. He floats like he's dead and then he'll start swimming a bit, and then floats again. I know he's going to kill the other guppy.

About a week ago we bought a Gourami and 3 Neons, and lost all of them due to aggression. At first I thought it was the Gourami that was nipping at the Neons, but then once he died, I thought differently.

We bought those 4 at Petco and they didn't tell us that we would have a problem with them, or that Platys are aggressive.

What can I do? The platy leaves the other platy alone, and Petco (where we got the Mollys and the Platys) gave us 1 male, 1 female. The platy only harasses the new fish.

I hate seeing the platy do this. It's not fair to the Guppies. lol Any ideas on what we can do?

[Cichlid Man]

Welcome!
I don't think your fish are dieing due to aggression, community fish won't generally injure each other unless breeding. I think your tank hasn't finished cycling yet, or maybe even someting more simple that that. What are your water parameters? Fine really doesn't help me, though I hope we can help you before it's too late for your fish. Next time if you're buying livebearers, buy 5 of each species to reduce aggression.

[bunyshaven]

We've had the tank set up for almost a month and a half now. We've had both platys and mollys for about a month and a week. The first time we added fish after that was a week ago. We brought water to be tested at Petco at that time, and the guy said all the levels were perfect and that we could go ahead and add new fish. So we did (the gourami and 3 neons). They died within the weekend. The gourami was constantly chasing after the neons and nipping at them, much like the platy is now doing. Petco had told us it was okay to have 1 gourami and that the 3 neons would be fine. After those died, we went and got our water checked again, this time at a lfs. Again, he said our levels were where they should be, but that ph was a little high, but that was due to the hardness of our water in the area. We picked out the 2 guppies that day and took them home.

When my boyfriend gets home, I'll have him test it today, so I can give you up to the hour readings.

But if it's cycling, does that explain the chasing and nipping? After I posted that message I went downstairs and sure enough, the orange guppy had died.

The platy has been nipping at the guppy's tail and body since we got them 3 days ago. And it is a male, based on the sticky thread I read afterwards.

If we were to buy more platys, do you think that would curb his macho man attitude and he'd leave the remaining guppy alone, or should we get more guppies anyway?

And is it possible he is trying to breed? Both sunset female and the blue platy female have a round belly, but then again, he's not attacking his own kind, just the guppies..er, guppy.

[Cichlid Man]

Ah, your pH could of resulted in your neon and gourami deaths as they prefer soft water. Also, your water conditions could of changed since your water test. Something as simple as overfeeding your fish can bring the ammonia levels up in a matter of minutes in an unstable tank. Also, you should of bought a group of gouramis, a lone one will get quite bored in a tank my himself, and the only thing he can do is chase the neons. Buying a group of at least 4 will reuce the aggression problem.
The platy could well be trying to breed, but I don't think we'll stress you're fish out too much if he is, it's probably the water that killed your fish, not the chasing, but then again every lil' detail adds up.

[Lydia]

Cichlid Man: I don't want to sound contradictory, but I don't think keeping gouramis in groups will curb agression. I have never had mine be agressive to any fish except each other. In fact I wouldn't recommend keeping them together. They seem to do better, IME, singly or with just one more. That is just my experience though. I'm not saying it can't be done, in fact I've done it myself, but I think that won't help fix the agression problem. That doesn't really matter anyways though, because they don't still have a gourami.

Maybe the guppies had tail rot? They seem much more susceptible to it than other fish. It just seems wild to me that a platy could/would kill a guppy because they seem to be very docile. I don't think I have seen my platies chase other fish, so that makes me think that something else is killing the guppies. Anyways I hope you can get it figured out! Good luck!


PS. Cichlid Man: who is that in your avatar?

[mousey]

well i have a male platy who used to be scared of everything until he got his own females. Now he beats up on the 3 of them, picks at the male swordtail and generally aggravates the guppies.
He has had a real personality change lately. he is a red wag platy.
The only fish he hasn't tackled yet is the female betta.
Every fish has it's own personality, and apparently they change too.
get a breeding tank and put him in it and see if he cools off.
mouse

[ronnfive]

IME, not all of the platy are bullies, they are typically non-aggressive fish but... some of them may do, and will chase its own kind preferably males and less females. Sometimes they tend to be aggressive towards smaller fish and that includes your guppies because they are tempted to nip long flowing fins. Platy breeding is almost always, and I don't see a problem with that. I would like to suggest you buy 2 females so that the other female can rest specially, after giving birth... But you are overstocked, and overstocking is one major factor of fish loss.

ronn