Oscar Goes Crazy After New Tank Mate

I have an 80 gallon fresh water aquarium. It has had my tiger Oscar(less than 6 inches) , firemouth and green terror in it for a few months. I just recently added a new red oscar(8 inches) and he is very calm but now my tiger Oscar is shaking and twitching (most likely aggressive behavior). The tiger Oscar does not go after the red oscar, they follow each other and nip very lightly. But when it comes to the tiger Oscar and the firemouth and the green terror he is constantly going after them now. I'm not sure if it's because the tiger Oscar and red oscar are male and female and want to breed. Can you help me figure out why this is happening?

 

I think you might have a breeding pair IMO.

 

Honestly , you've got yourself an overstocked tank , with 2 Oscars , 1 Green Terror and 1 Firemouth. It's only going to lead to territorial disputes and aggressive with so little to claim their own. An Oscar requires a 125g at the minimum. I think if you don't fix the stocking issues , you might be in for a surprise sooner or later.

 

Honestly , you've got yourself an overstocked tank , with 2 Oscars , 1 Green Terror and 1 Firemouth. It's only going to lead to territorial disputes and aggressive with so little to claim their own. An Oscar requires a 125g at the minimum. I think if you don't fix the stocking issues , you might be in for a surprise sooner or later.

No, 2 Oscars can live in a 90 - 100 gallon.

 

No, 2 Oscars can live in a 90 - 100 gallon.

that's your opinion , I wouldn't put two Oscars in a 90g , they require more room I say 125g at the minimum some on this forum say a 150 gallon and some say 180g for a pair of Oscars.