Biggers always better but just 2 fish in any tank needs something else to focus on unless paired or their mild. But those not that aggresive , its not like a grammode and a red tiger or a haitensis in there , thats relentless aggression ,it wont stop,, with just 2 they would need other focus, but could work 75, but yeah bigger the better , depend on the keeper too , me myself love to overcrowd but big tanks n overfiltrate too many spectators wow it . Started wit red snakeheads pikes and gars in early 90s .Liked the death fish, in 55 to 90 gal, young trial in error . First cichlid a strigatta pike he lived with a black rhom pirranah for a year plus it worked then sold both but in a 90 gal, not responsible on my end but worked ,now every where u read on net say it wont work, but in reality it did, but my fish i was the keeper they loved precooked shrimp earthworms and low ph easy pike 12 inch blk rhom 8 . Bigger is better , all fish have different character traits but 8 out of 10 he should see long life in those two.
