Tbh, it’s only a matter of time. The redtail will grow much faster than the arro so even if they are fine together to start with they won’t be for long. Over 40 yrs I have had rtc that didn’t bother other fish …. But only till he got to 6” and then ate a 5” dat. My 10” rtc lived with an 14” arrowana until he got hungry one night. They don’t care that they can’t fit them all in! Then I have had a 30” redtail living peacefully with 8” fish and never bother them……… maybe not worth the effort.
