Ammonia/NitrIte are 0, NitrAte 20 (about normal before water change) Fish: 2x Clarias (12" each) 2x Oscars (5" each) 1x Ornate Bichir (12") and 2 Kissing gourami (5" each) Tank 6x2x2 1/2" pea gravel substrate, fake plants, lots of wood/rocks. Filtration 1xFluval FX5 and an Aqua one 1200.

Only problem is that the water is really cloudy I've tried big water changes - up to 90%- and it cleared for a day then was cloudy again, have cleaned the filters (in tank water) and luckily water chemistry is stable, it just looks unsightly. Any ideas anyone?

any new food?

No. Water was cloudy before I got the new blood worm pellets so don't think it is them. It has been like this for about 3-4 weeks but I've exhausted all my ideas. We can get it clear but within 24 hours it is murky again.
Tried light/no feeding (as much as possible with big hungry aggressive fish!) thorough vac of the bottom (that was funny - involved a step ladder and me dangling over the tank) even scrubbed the sides...

That's strange. You're sure that all the filters are doing their job properly i.e. the inlet and outlet pipes are attached properly? Might sound like a silly question but you'd be surprised...

is it cloudy all the time? a few weeks ago I had really cloudy water in my tank and couldnt figure out why. turned out the tap water was full of bubbles following work on a mains pipe. it went on for weeks and looked really weird.

did you find the cause of this indi?

It is cloudy all the time. As far as we can tell all filters are working spot on.

I wish my camera was working cos than I could take pics of the rocks and ask Mary about their suitability in an aquarium! There are none that were obviously not fish safe though.

Tank is emptying now, going to remove all decor apart from slate and see if it helps.

Sounds like a "fun" job.

oh yeah LOL...

good job you dont have phisjy's fish!

HA! The Oscars bite! So does one of the Clarias...

Well I can't think of any rocks that would cause cloudiness unless they were quite soft to begin with and are leaching dust particles. As regards suitability, so long as they're not calcareous in origin (you can test with a few drops of API Nitrate bottle #2: if it fizzes, they're limestones) or have a high heavy mineral content - they'll appear quite glittery under the light - they're probably ok.

Oooh, all those years of study weren't wasted after all!

i've been watching this one indi but i have no sensible suggestions apart from empty and refil with just fish & water then add one thing at a time gradually.
I was wondering about oxygen but only wondering...