I have 2 5" blue ones in my pond. Somedays they are pale but on sunny days they get bright blu. Fights back when bullied or confronted by jags. But stays mostly undergrowths...very shy and faassssst......acts similarly with my 5' blue ahlis.....
Ceptopsis are very cool, You might remember them on that program "Abiss" a few weeks ago on the Disco Channel as the fish devouring dead meat thru a nylon net that they had chewed through. Their enitire skull is one massive muscle. It's from Peru/Brazil out of the Amazon. We get ours out of the Nanay river I beleive. It will get about 1.2-1.5ft. Females have more girth. They are a deeper water fish that are active in the dark. I had one that swallowed a lazor cory the size of his head and lived to see another day. Big fish only with this guy. They look like a shark when they eat.
Cetopsis coecutiens is it's scientific name. Great fish with it's agressive personality and great coloration.
Look up Cetopsis coecutiens . It's a South American catfish , and are related to the parasitic Candiru catfishes. They grow up to 10" long, and are pretty active.