I did reply but it went on someone elses comment thay put so nice can you see the comment I returned for all to readA pair of firemouths or a pair of texas could easily fill up a 240 litre tank on their own. 2 acaras, 2 convicts, 2 texas and 2 firemouth can be quite the bioload and also if you get pairs of firemouth or acara they can get rather crazy (like maniacal) with eggs so be warned. Then dont get me started on convicts, blacks are a colour type as far as i know so they will also be nuts if paired.
As for the driftwood that is just a harmless mould and is common in new tanks, it will disappear soon