I have a few general questions about my neon tetras. I have a school of 15 in a densely planted 100L. All parameters are as normal but they seem to be struggling. I’ve experienced this before when I’ve kept them but I didn’t really know what I was doing back then so I put it down to that. 2 have weird white patches (looks like when one got attacked), one has bumps and lesions all over and is very skinny, not sure how that one is still alive, and one is bloated with a bent spine to one side. Could this be my water? My water is quite hard and high ph so I was concerned about them but was advised that stable was better than trying to change them and having drastic swings. Should I try and change ph naturally with those leaves (forgot what they’re called)? I already have driftwood in the tank. Or is it just that neon tetras are fragile? I’ve already tried medicating with ESHa 2000 but can’t see any change. I’ve had them for almost two years I think, didn’t realise I’d had them for that long to be honest but they’re meant to live for 5 years.