Hmmm I couldn't see a nitrate test. Just ammonia and nitrite in pets at home. Got a pH test but that won't tell me much about the water quality will it? That's just to see if it's too acidic/alkali? Maybe my store is rubbish. Il go to the pet shop where I bought my goldfish, they have loads of fish stuff.
The fish that went missing was very small so he could have just got stuck somewhere and when iv poured fresh water in, iv dislodged him maybe. At least he's alive and plec hadn't eaten him! Ha.
I also bought some different plec disks and he has eaten a bit of one so that's a good sign.