Foley Maybe i have taken it the wrong way because that is exactly my thoughts on the subject.
If he has five Firemouths in a tank it would have to be around 6 foot anyway because of territory restrictions it would be all out war.
Unless he is keeping juveniles which is even more stupid saying they produce as much mess as a oscar.
I kept a pair of Oscars and a common plec in a 5ftx2ftx2ft tank before and the mess was horrendous,they had white sand originally and it was black inside a few months (i had to change it to gravel),I had a external and 2 internals and i still only fed him once a day max and that was a small amount Cichlid pellets...i had to do water changes 3 times a week to keep it clean.
I have kept both a much bigger Kissing Gourami and a Firemouth before with loads of platys,swordtails and mollys and 2 juvenile clown loaches in a 4ftx1ftx1ft foot tank and i had no mess whatsoever,just the usual gravel clean and weekly water change.
The reason i made the thread was because i have never kept any type of shoaling fish with a Firemouth before and i was concerned about how my Angel would get on with them.
I'm aware of stocking restrictions but IMO that doesent apply to this set up with just 3 6" fish and 5 tiddlers.