With variation among individuals of a species, it’s hard to say for sure when both cap at about the same length and weight.
I would go with the largest species on average rather than which has the largest individual. One large manny doesn’t mean that all can get that big. But given that most piraya are biggest, that is the one I’d go for. Between that and a rhom, I would just pick whose behavior you like more. Both hit about the same size in tanks.
I have no real world experience with this, just going off of my searches.
Now if you want the biggest serrasalmid (pacu, silver dollars, piranhas), get a pacu. I’ve personally seen them above 3 feet, and this is a common size in big tanks.
I would go with the largest species on average rather than which has the largest individual. One large manny doesn’t mean that all can get that big. But given that most piraya are biggest, that is the one I’d go for. Between that and a rhom, I would just pick whose behavior you like more. Both hit about the same size in tanks.
I have no real world experience with this, just going off of my searches.
Now if you want the biggest serrasalmid (pacu, silver dollars, piranhas), get a pacu. I’ve personally seen them above 3 feet, and this is a common size in big tanks.
