You set your tank is 160 cm, that is 5 feet. How wide and high is it?
Okay, where do we start? Your tank is miles too small for the fish you've got. Off the top of my head, you need a tank of around 600+ gallons for the fish you've got. Okay, the pacu may not reach 3 feet but you have to take into account that that's how big they can reach. Put it this way, I have got six 4 inch Oscars, four ClownLoach (two small and two large) one Jade eyed Cichlid and two Syndontis catfish and my nitrate levels are 40 ppm at the end of the week. Your Oscars should be around 6 inches, maybe more I know. I just can't see how you could possibly keep your water in good condition. You would have to be doing around three water changes a week.
We don't jump on people on this forum, we just try and give advice where it's needed. I would advise you to think very carefully about your situation. Nothing but bad is going to come from it if you don't reduce your stock dramatically. I'm not going to echo what's on this website, have a good read and you should get a good idea of what you should have in your tank.
