In this episode I’m basically getting the “engine” of the home discus aquarium properly dialled in before the fish go anywhere near it. The tank’s only been running a few days, and straight away we get that classic new-tank surface scum — oily, bacterial, totally normal. I show you how I deal with it without panicking: bubbles for agitation and a surface skimmer to clear it fast, which also improves gas exchange and just makes the whole thing look cleaner. Then I run through the gear that makes this setup stable long-term: the big canister filter with the prefilter and built-in heater (discus need that extra boost up around 28°C), auto top-off to keep the water level perfect and stop that nasty evaporation line, and UV sterilisation (I’m doubling up because discus can be a bit finicky). I also get CO2 running again — nothing crazy, just enough to help the plants — and swap to finer prefilter sponges because I actually want them to clog and pull crud out (just clean them weekly, don’t be lazy). Finally, it’s fish-moving prep: I transfer the discus gently into a holding tank so I can break down the old setup without stressing them to hell. While doing that I uncover the madness going on in the old tank — generations of plecos and a full-on Stirbai cory army (19 counted!).