Do you think 3 kelerbi would do better with the oscars in the 8x3x2In the end , these fish should not be kept together when the Bass can get slightly less than double the size of the Oscars. They would be short term tankmates rather than long term tankmates. How large the bass will get will depend on how well you feed them. If kept properly, they should get between 61-71 cm and weigh as much as 9 kilo. These fish require a lot of food to reach this size so underfeeding them will only make them grow slower but will in the end, make them unhealthy over the long term. The tank you mentioned is about right for one adult of these Bass. What you would need to do if you were to raise small ones with the Oscars is provide a lot of hiding places for the oscars that the bass can not get to. Domestic raised Oscars only get on average 40-45 cm. ( Wild Astronotus get slightly larger.) So now you see how they are not really compatible as adults in a tank your size. If you were to do this combination, be prepared to be rehoming some fish at some point in the future.
Hope this helps.
To be honest, Oscars can be aggressive towards other SA cichlids of smaller sizes while not really being an overly aggressive fish in general. ( I've raised and bred many Oscars only to find out that their reputation is poorly discussed in the hobby.) Peacock bass species on the other hand are more aggressive fish. In order to get a good harmonious tank, you would need to get Oscars that are larger than the Bass but not large enough to eat the smaller Bass. You would also need to add A LOT of hiding spots that can not be used by all the fish in order to help protect the smaller fish while giving the larger fish a place to call " home".
" is that they have multiple personality syndrome. Some get extremely aggressive towards any fish, including other kelerbi, that are smaller than themselves while others do fine with everybody until it's feeding time. So if you are going to mix the 2 species, the kelerbi would be the ones to choose since they get about the same size as the Oscars but again, be forewarned that it could go South at any moment. 
My oscars aren't the agressive type they get picked on by my pleco lol but they usually defend themselves so I'm not really worried about the bass being agressiveTo be honest, Oscars can be aggressive towards other SA cichlids of smaller sizes while not really being an overly aggressive fish in general. ( I've raised and bred many Oscars only to find out that their reputation is poorly discussed in the hobby.) Peacock bass species on the other hand are more aggressive fish. In order to get a good harmonious tank, you would need to get Oscars that are larger than the Bass but not large enough to eat the smaller Bass. You would also need to add A LOT of hiding spots that can not be used by all the fish in order to help protect the smaller fish while giving the larger fish a place to call " home".
That all said, I have not kept the kelerbi personally but the " word on the street
Probably will just go with 1 kel 2 oscars and some other cichlid or dither fish
Oscars are funny fish. They too have many personalities. I was up to 13 breeding pairs when I moved and had to leave them behind at my mentor's hatchery. I've had some that bit my hand every time I tried to clean their tanks and had others that shied away. Some that would beat up anything in their tank and some that got beaten. I had one that would cuddle up inside my hand. I had one that sucked my thumb when I put my hand in his tank. ( Not aggressively, it just seemed to like my thumb in it's mouth. LOL ) I had one pair that after I removed their fry, the next day I added about 2 dozen comet goldfish which hadn't turned gold yet to their tank to feed them and they instead corralled them and was treating them like their fry. 
So you can see, all kinds of personalities. Mine love to bite me and they love pets, when i try to change the water the purposely splash me lol. Very cool fish
Btw what is the minimum tank size for kelerbi peacock bass because I not not be able to get the 8x3x2 depending on the shipping because I am getting it from outside the country
It's not as much gallons as it is floor space. I wouldn't put them in anything under 6'L x 24"W ( 183 cm x 61 cm. )
72″ x 24″ x 25 are thes dimensions fine?
As a minimum. Make sure your tank is covered. Peacocks like to fly even tho they don't have feathers.
( They are jumpers. )Would 2 oscars and a kelerbi work in that?As a minimum. Make sure your tank is covered. Peacocks like to fly even tho they don't have feathers.
If the 8x3x2 does not work is this fine?As a minimum. Make sure your tank is covered. Peacocks like to fly even tho they don't have feathers.
In theory it should due to the length and width but only being 1' in height, that could cause a problem as the fish grow. If you use any kind of substrate, there will be less than 1' of water. That could make the fish very uncomfortable and skittish.
Is this better?
