Also one of them has Hole in the Head disease. I got both of them for free because of it, have been told to keep on top of my water changes and feed good quality food. My local aquarium also has a specialist vet come out once a month so have booked in to see him too.
Not sure how available they are over there but a large synodontis cat or 2 would work well, like Syno. eupterus or similar. Or a good sized bichir, mine does a fair job finding and eating leftovers. Re: the pictus, with the oscars you might try and find 4 line pictus, they get bigger than the normal spotted so less danger of the O's trying to eat it.
I didn't, but I will now! I clean the gravel nearly every water change anyway so would guess it wouldn't give gas a chance to build up.
And thanks heaps for all your suggestions guys, will be going down to the local aquarium to see if they stock some of the suggestions!