Cichlid dilema

Question
I went to petsmart yesterday and was looking at buying green terror cichlids.  I have a 29 gallon tank and the girl told me that would be sufficient for the two fish to live together.   I thought this was strange, but I figured she was the expert.  I have been reading more about it and it looks like I picked the wrong fish.  I had heard that you need 1 gallon of water per full grown inch of fish and the way I figured it, if they both reach 10 inches then a 29 gallon should be sufficient.  Thanks for you help.

Answer
Hi,
I have a 14" female green terror paired with a 16" male, but I have also had green terrors that have lived for years and never got any bigger than 6" and were perfectly fine like that.

Point being, if you got lucky, that would be fine. Green terror won't get any bigger than they feel they can get in a specific environment. The one thing I would worry about is aggression, which should be fine as long as you dont have 2 males, and the tank has lots of cover.

Just for the record, the 1 inch per gallon rule is just a guide line for beginners. For example, one of my rays is about 25" WD and I wouldn't even think of putting her in a tank below 500 gallons. On the flip side, I have had two 3" convict cichlids live happily in a 5.5 gallon tank for a long time, i think it must be around 5 years now.