Stocking my 180g

You mean english gallons right? That would make your tank 213 american gallons. So you could add maybe 5 more fish? I'd suggest some hillstream loaches, they look cool.

No, as most people here are american i worked out the size of my tank in american liquid gallons. Unless i have done my maths rong my tank holds 144 english gallons or 180 american liquid gallons, My tank is 6' x 2 1/2' x 2'.

I would love to have an oscar but if this causes problems i'll get something diffrent.

Would a red devil be ok?
 
Red Devils are too agressiv, I'd stick to something along the lines of large-ish SA (chocolates, geos) or small CA cichlids (rainbow, Cryptoheros) of lesser aggression.
 
Ok, i've just filled my tank and am going to move fillters and fish from my old tank tomorrow when the water is at the right temperature. So how long should i wait before adding another fish?
 
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