Venes average around 18", can get to 24". Plan on a 125 gal for this guy. Sevs are great with pikes, as are GT, and many species of catfish too. Mostly plecos cause of their armor, but others do fine too. I am sure silver dollars would be good dithers. A large Clown loach of like 6"+ could be. Leprinos. Alot of fish would be good, but a pair of pike would be best, goodluck with that though. Growth rate is the fastest I have seen in a fish as well, my Johanna has grwon about 5 inches in about 3 months.