I'm enjoying researching and learning about fish - daydreaming mostly. I've read through many posts and noticed many people really like the severums. Is there a difference between the gold and the green? is it just a coloration difference or are the different species with different temperaments?

The fish themselves regardless of species have different temperaments. I currently have a 6"+ green severum that gets on with my Oscar and other tank mates perfectly. However, the green severum I've just rehomed of the same size was regularly fighting with my Oscar and other severum hence the rehoming.

I think it's the same for all cichlids. You get "good" ones and "bad" ones. Unfortunately you won't know what you've got until they're in your tank for a few days.

If you get a severum that's compatible then they're really lovely looking fish that get better the more they grow.

I love Severum's,and one gold red spotted which is about 8 inches long. All of them are more than capable of sticking up for themselves against the Oscars and I don't find them at all aggressive towards other fish in the tank.