'Cichlids' is a VERY, VERY big group of fish, so there are tons of types, some that would work well in 175 litres, others that wouldn't at all. If you like cichlids, there are some rough groups that you should select from, then persue it from there. The groups I can think of are:
CA (central american): A mix of all sizes, relatively easy for a new commer, biggest problem is aggression.
SA (south american): examples like the friendly oscar, to the SA dwarfs such as rams and apisto's.
African (malawi, tanginika, victoria): The main lakes where the fish come from, often colourful and you see dense stocking
Of course these are generalisations and some fish will not be suitable for your tank, though if you do like the look of cichlids, try researching more on which group you like then come back with any questions.
[URL="http
/www.cichlid-forum.com/profiles/"]http
/www.cichlid-forum.com/profiles/[/URL]
If you do like cichlids look around there, which should help you.
Also:
http
/www.cichlid-forum.com/articles/quic...erence_list.php
on the cookie cutter set ups, for what size tank you have (though your's is an odd shape, so do bear that in mind as it will affect which fish you can keep. Your tank is on the small size for afew cichlids, so it's best to research and ask opinions on your stocking.
Note: This is just about cichlids, I am in no way an expert, there are vast amounts of fish you could have in your tank, its up to you to choose, if it was me, personally, I would probably dump some oddballs in there.