You take some awesome pics, duanes. I'm loving the blues and violets in the regani and zonatus.Most Vieja (Paraneetroplus) types need lots of space.
A single specimen in a 75 might work, and with patience become quite dog like.
But in that small space, aggression would become an issue with more than one.
Even in a 125 luck would need to go your way, to avoid aggression.
In a 150 gal I've had zonatus, argentea and regani pin larger managuense and dovii in corners.
Don't get me wrong, Vieja are some of my favorites, and some of the most beautiful, but space is the key, or they become sociopaths. The only way I'd try to keep more than one species together as adults, would be in a minimum, 300gal.
some I've kept.
argentea
bifasciata
breidhori
regani
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