not the best place to go for important information. average recommended min tank size, for an adult, is 120-155L
So where IS?
2005/2006 LOTS of research (internet/printed/verbal - fish clubs) on one of my fave fish RTBS
First half last year talking to an owner/operator of a fish shop located other side of the city, about this that etc, came up I was interested in breeding redtails, he told me had article on keeping/breeding red tails at home from a 1960's fish mag (cant remember exact one) would happily make me a copy - this artical more than doubles any information had already found, its very relevent even though its 40 years old (give or take), why because at this time red tails were not mass produced on fish farms but wild caught and some home breeding, something rarley done today.
Up until july last year I was growing up male two red tail (dont try this at home folks) both in a 4'/55gallon (no aggression, often swam as a pair), I had them at both over 4", no white tips on fins, basically on the lower end of sexually mature.
June I introduced one of these fine straping young lads (well I thought they were) to my above mentioned female (she had been going through cycles of getting plumper and thinner, plumper, thinner etc it was kinda obvious what was happening). At the time she was living in my 3'/40gallon discus community so I yanked everybody to different tanks introduced the male to the female tank set up basically as per instructions

AND
nothing 
I left them at for three days, she was plump (possible not plump/ready enough, or he wasnt big/ready enough) no chasing, no aggro, no nipping, no damage, no death just sad me, oh well transferred the boy back to his 4' tank
At this point I am sad to say I had an emergency forced relocation (before I had another chance) of three states 2000 odd km (Queensland/Tasmania), to be organised in less than 2 weeks, basically ment selling almost all my aquarium equipment and all my fish, you can bet I was gutted. Some of my stuff is still in storage in Queensland, including the copy of the magazine article.
I am currentley in the process of growing up 3 red tails to try and breed
I have kept red tails since I started fish keeping, I have never lost a single fish to their aggression, I have kept two adult males in 4' community, I have kept an adult female & unsexed juvi in a 3' discus community, I have kept adults in 20gallon communities, all with no loss, if fact the only aggro past their base territorialness (that I've seen) is some dislike bristlenoses (this may transfer to plecos but they are big enough to ignore it). If a RTBS is allocated a hollow log or similar within a tank by and large most of them (fish can have individual personalities, look at cichlids) will call it home, usually they will become VERY aggressive to this home (except to larger fish, and then they may still fight) if a fish come into this home its immediatly chased off, but not usually very far. If this is done they usually end up IME less aggressive that a blue acara for example
Basically, they are much like many american cichlids in way, cater to their needs, thay are a very wonderful rewarding fish, dont cater to their needs and they can be VERY bad.
Do I proclaim to be an expert, No
Do I claim to be omnipitent, No
I do claim to be researched better than most people on TFF with regards to RTBS, and I personally believe that gives me the right to disagree with your opinion. <mod edit>
NB Any information gleaned from this post should be taken as an opinion, a researched opinion, but still an opinion, not a fact
Please all excuse my rant.
Andrew