MEAN AS HELL
You may want to take a look at this.
http://predatoryfish.net/ibforums/ These guys seem to deal with what you are looking for.
SAMPLE: Otheris, Otheri
Max. size: 67.0 cm TL
Environment: demersal; freshwater; brackish; full salt water
Climate: tropical; 24 - 26°C to near freezing
Distribution:
Worlwide.
Biology: Inhabits large rivers and lakes . Also occurs in estuaries.
Dangerous: Extreme caution!!!
Description: razor sharp teeth, scales like metal armor. glowing red eyes.
Maintenance: This fish must be kept on its own in a secure aquarium!! Caretakers of this fish must take extreme measures when doing tank maintanence. Most invest in a pair of welders gloves for water changes.
No heater, filter, air pumps are required. Change water once a year, and keep lid weighted down with 100 pounds or more.
Feeding: Anything and everything. I once had one that ate itself!
Personal observations:
Ok, this fish is THE MEANEST fish on the planet.
Hareball-"this fish just jumped out...it got in my salt water tank and killed everything, and ate my live rock. Im scared to go into my room now".
Mojo-"I swear it was going for my crotch!"
Ed-"I screamed like a little girl!"
narc- "it made me eat my own #%$&! "
Bill-"it beat the #%$& out of me, then it crapped on me!"
This fish can beat up all other fishes. There is no competition. Period.