as of now its pirahna. speices i dunno yet - still researching. if i end up going against the pirahna idea - then who knows. will be a predator regardless. so lets put it this way a 55 gallon, predatory amazon biotope. 55 gallons for now - will end up with a 200-300 gallon within the next year. so - if the fish is small now but will grow to 20" or a little less, and its got teeth, it'll be considered. im also thinking a black water setup? dunno on that yet tho - actually buyin 2 55 gallons, so could do one of each. one black, one clear