recently my 2 larger tiger oscars(12"-10") started picking on my smaller red oscar(6") while ignoring the smallest one(4.5" albino). the reason for this has eluded me so far but i think it might be a territorial thing. i was wondering if i put them all in a larger tank say from my 6' 190 gallon to maybe an 8' 250-300 gallon if this might lesson the tension between them.

any input on this would be appreciated.

this is always a risk you take when you mix several Oscars.Have you actually got a 300 gallon tank set up and ready? If you haven't, it would be a very expensive venture if it doesn't work. Giving fish lots of space won't necessarily stop aggression. At the end of the day, 8' x 2' x 2' is tiny when you are talking about a fish that can exceed 1 ft in length. If you are having serious aggression problems, I would personally think about rehoming one of the Oscars, rather than trying to put them all into a slightly bigger tank.

However, if you have already got the big tank set up, give it a go, it might work but you will only know if you try

well after confering with my wife(who really wants my 190 gallon for her africans) i've decided to try and put my o's into an 8' 250 gal tank to see if this helps with the aggresion thing. there has been no serious damage to my red oscar so hopefully the larger area will eleviate their attitude

i'll update as time goes by

I have read that there are no aggression problems between oscars when you keep 6 or more (except when a pair breed). My friend works in a fish shop and they have several in a tank and he confirms this, he told me they get no problems of fighting. These fish vary from 6 inches to about 10

So if you get the new 250g think about putting 6 oscars in it. It will mean a lot of work with water changes tho. You can tell us if this no aggression with 6 oscars works?

Actually penn did you have any problems with aggression when you kept all your oscars together, and do you have any aggression with the 4?