This question is too broad. Their are a million variables to it.
To calculate follow the directions below:
You first need a well defined definition for 'personality' pertaining to and specifically related to these 2 species of fish. And you would need criteria for grading these two fish by 'personality'.
Then do a trial study of at least 1,000 arrowana and red tailed catfish chosen randomly through a computer algorithm (for ensured authenticity of this study). Design a database with 2,000 profiles and get group of 1,000 judges with no particular attachment to either arrowana or red tailed catfish. All these judges must have no bias or background history in fishkeeping. Give each and every judge 1 arrowana and 1 red tailed catfish and allow them equal, uninterrupted time with each fish. Each judge will keep the fish in seperate tanks in a sucluded room with no distractions such as tv or phones for 2 weeks. The first day they will only have access to 1 fish, the second the other fish, the third the first fish again, and so forth... at the 15th day they will be given a url and told to enter their findings onto the secure database and grade the fish from 1-10.
Compile the results the 1,000 judges have entered online and find the mean between the 1,000 graded arrowana and 1,000 red tailed catfish.
Doing this will yield foolproof, solid brick results with no other possible explanations and absolutely irrefutable evidence.
This question does NOT have a simple 'one or the other' answer, their is too much bias, you're posting in a catfish forum asking whether catfish or arrowana have better personality. Thats like posting in a democratic forum about whether democracy or republicanism is better. Their is far too much bias in this statement.
Rtc have great personality towards their keepers, but not towards their tankmates small enough to swallow lol.
