You're going to always get a lot of different opinions on these boards. Some folks are hardcore purists that test their water daily and try to duplicate exact conditions in the wild. Others just throw their fish in and let the chips fall where they may. Generally speaking, you're going to get a good understanding of the basic do's and don'ts on this board. It's up to you how much fussing, time and perfectionism you want to put into the hobby. IMHO, as long as you enjoy the tank and the fish aren't too stressed out, that's all that matters.
Whether fish are 'happy' is very subjective. Whether fish are stressed out would be easy to determine, even by beginner or casual fishkeepers.
'Generally speaking,' loaches and cichlids together is fine. But there are always exceptions. If you had asked me whether a gourami and an oscar could co-exist (never tried this), I'd say you'd have a dead gourami by morning 99 times out of 100. That's what makes this hobby so special - it's full of surprises and no two situations are ever exactly the same!
Whether fish are 'happy' is very subjective. Whether fish are stressed out would be easy to determine, even by beginner or casual fishkeepers.
'Generally speaking,' loaches and cichlids together is fine. But there are always exceptions. If you had asked me whether a gourami and an oscar could co-exist (never tried this), I'd say you'd have a dead gourami by morning 99 times out of 100. That's what makes this hobby so special - it's full of surprises and no two situations are ever exactly the same!