Aggression with tiger oscars

[busymom23]

Ok, here's my problem: I have just moved my two tiger oscars from a 55 grow out tank into a 300 gallon. They are more aggressive in the 300 than they were in the 55! They are constantly chasing anyone and everyone they come across and I don't understand why! Below is a list of everyone in the 300:
2 tiger oscars6-7 inches
1 albino oscar 4 inches
Rhino pleco 7-8 inches
Jack dempsey 5 inches
Blood parrot 4 inches
Black ghost knife fish 8-9 inches
6 silver dollars 2-3 inches
The only one the oscars do not mess with is the knife fish. There are plenty of caves and 4 plants with pool filter sand as substrate, fx5 and 55 gallon sump as filtration.

 

[Rivers2k]

How long have they been in there? Possibly just establishing territory.

 

[busymom23]

I moved them yesterday...how long will it take for them to establish territory? Do you still think it's territory attitude when they're chasing everybody, no matter where they are in tank?

 

[Jmunroe]

They are trying to claim territory. They probably will settle after a couple days. You will probably have issues with the 3 oscars being together. 3 is next to impossible to keep together when the mature. 2 will likely gang up on one and then it's hit and miss if the remaining 2 will get along together. Keep an eye on them and have a plan for the outcast fish.

 

[Rivers2k]

I was going to say the same about territory a few days it should settle down. I haven't heard that about Oscars before but I am no Oscar expert. But seems like that is a big enough tank for 3.

 

[busymom23]

Yea, I've put it aqadvisor and it doesn't give me any warnings about keeping 3 together. I have a 150 that I could keep the smaller oscar in if they don't stop picking on him, or the 55 but he'd be all by his lonesome, which I didn't really want. I really hope that they are just establishing territory and not just that mean...hopefully they will calm down.

 

[Jmunroe]

2 males will fight, a male and female may accept each other and will oust the other female. 2 or 3 females may get along. 300 gallons won't be big enough if they decide to fight. Most large territorial cichlids act this way. They may be alright no matter the sex until they reach maturity which will start to happen for oscars any time after 12 months and they reach maturity at around 18 months. Most oscars you buy at 1-2 inches are already approx. 4 months old so after you've had them a year they may start to act different if not before. Some oscars just don't like others at a younger age.

 

[busymom23]

I have no idea if I have males or females. The 2 tigers have hung out together fine since the day I brought them home. I bought all 3 January 6. Crossing my fingers that they can all live happily!!!

 

[Jmunroe]

And that's the unfortunate thing with oscars that makes it even harder... you can't tell the sexes until they breed.