Reuniting 2 Red Bellied Pirahanas

[Delaneia]

I had issues with a dominant RBP so I seperated the pair, the smaller of the 2 has grown to be about the same size as the dominant one and a friend offered his 55 gallon to me. Right now the 2 are in seperate 30 gallon tanks (they are approx 6 inches long) and have been seperated for about 3 months. Is a reunion a bad idea if I put them in a 55 gallon?

 

[Gatorbait]

It all depends. There is really no set in stone answer.

IMO, it's not a good idea to have just 2 rbp's as the dominant will always kill the sub-dominant, ime.

There's another poster in here that has had luck with 2 but not 3. (I think maybe it was because it was a breeding pair tho and they would attack anything else)

As far as size-wise with the reintroduction of more mature rbp's, it's within range. I wouldn't try anything more than 1.5" size difference between the largest and smallest in a shoal. (I know that doesn't apply here)