2 pairs of O. Clowns in 75 gallon?

The odds are stacked against you here but there is a chance,

I would suggest shuffling the landscape around when you introduce the second pair so they can redistinguish their terratories and as long as they stay within the newly established boundaries it could work.

There is always a slight possibility the two younger fish may just be on the lower scale of the hierarchy socially and will stay neuter. In the wild these fish live in groups of up to 26 on a single anemone with only the largest two being of sex, If the smaller clowns are 7 months they will not have sexed so there is a slight possiblity it could work. The larger two will bully them and keep them small as is natural but there is a chance,

Its all down to whether you want to risk possible deaths.

good luck

 

I have a pair of Black O's in my 75gal. and I added a pair of Picaso clowns (small unsure how old) a little less then a year ago and have had zero issues. I'm guessing this is because the Black clowns didn't feel threatened by the smaller pair. They now sleep in 2 mixed groups.

I'm not saying that It will work, just that I have had no issues with it.

Just reread your post and seen that the smaller ones are already in the tank that both would be in. This might be more of an issue then due to the smaller ones already establishing territory thus being less likely to back down.