Cichlids are certainly interactive, but I'm not sure they're 'friendly'; certainly not always; our oscar recognises certain people (he liked my son, until the son bleached his hair, now the fish goes mad when he sees him
) but basically hates everything and everyone; especially my mum's dogs and the water changing stuff.
On the other hand, my old angel seemed to love me, although it was probably just begging for food really!
Bettas ae really friendly, that's true and goldfish; especially fancies. Some of my favourite fishy friends ever have been fancy goldfish, although I don't keep them now (too many health problems, I find).
I would not recommend goldfish to a beginner unless they are willing to pony up the dough it takes to properly raise them, goldfish are quite expensive to keep, especially if you want to keep more than one, they are very messy fish and require a far more active maintenance schedule than most other fish. They are very awesome to keep though, full of personality, they will eat out of your hands, very interactive. Some fancies are quite hard to keep, and are very sensitive, but there are a few quite hardy species, like the Ryukin (one of my favorites). 1 goldfish requires no less than 30g (so they say), however, I would recommend much more due to how messy they are, the smaller the tank, the more maintenance it requires, and the more time you will be spending on keeping the water quality up. They also require over-filtration, so if you have a 30g for 1 goldfish, I would recommend a filter for a 75g. If you have a bigger tank for them, like a 75g (which I recommend), then a couple filters for a much bigger tank would be expedient. They are not simple fish to keep, and they do require a lot of maintenance, and the fancy variety are very sensitive to changes in your water specs. Given all of this, they are fun to keep, and I enjoy mine very much... it's a very fulfilling experience.
Guppies are simple to keep, my sister used to keep this when she was little, and quite successfully, she used to breed them as well and sell to one of our LFS (I think she was like 6 or 7 years old when she was doing this, so it's not at all too complicated, and they don't need a tank that is very big. I would recommend a 15g, although some say that 10g is suitable... (the bigger the better, and the extra 5g goes a long way). However, guppies breed a lot, and you'll have to be prepared to manage this. All in all, they are fun, playful and quirky fish. I love them.
Bettas are nice, they are beautiful and they can have big personalities. 10-15g tank would be suitable. (always, the bigger the better.) Although, you can't keep a lot of things with them, well, not anything really, snails... so this is a limitation.
Cichlids are very nice, and I've heard a lot of successful beginner stories with them, they are also chalk full of personality and playfulness. However, to keep a community cichlid tank you will need a 55-75g aquarium.
There are pros and cons to keeping any fish, and it is a very expensive hobby, it's best to choose wisely, and to choose a fish that will be within your budget to care for correctly.
