I wouldn't keep a big wolf with anything that I would care went missing or was torn to pieces. Kind of like an African Lungfish...
We collected a bunch of them in Uruguay and unless housed individually the larger ones would eat the smaller ones (and anything else). Like a 3" wolf fish will eat a 2.5" wolf fish. Or a 1" one will eat another 1" one!
What's interesting is that we collected both Hoplias malabaricus and lacerdae in Constituction (off of the Rio Uruguay) in Western Uruguay. Lacerdae gets to about 3' long (!) while malabaricus gets to ~2'. If you look at the gills from the bottom of the fish, the gill plates come together for malabaricus and are straight for lacerdae (or maybe it's the other way around). Otherwise, they're pretty much indestinguishable otherwise (and I'm sure interbreed).
The hobby has decided that H. lacerdae is the holy grail and worth hundreds (thousands!) of dollars. Folks spent a lot of time looking at the bottoms of wolf fish to try to pick out H. lacerdae to bring back. And in the end most of them ate each other along the way
I brought back a baby last trip and (my own fault) it jumped out...
Matt