I only did water changes once every week (usually just 25%, and I always conditioned the water) and would siphon all the gravel during the water change. I thought that was enough to keep the water clean since I read (without much context, and I didn't look into it further) that "too many water changes can stress out your fish, so you should only do a partial water change once a week." That water quality must've been so bad and I'm realizing probably the cause of that
betta's
fin rot. : (
Still infinitely better than those people who take out the fish and just WASH EVERYTHING in the tank. At least you must have had some nitrogen cycle going in your gravel.
I don't own a test kit.
I have NO IDEA what my
nitrate levels are. Never have. But my fish don't die, my plants are healthy, and I carry out water changes regularly, so I don't care. But it feels like a dirty little secret!
Honestly, I think tests are only a necessity while cycling. Once that's done, the chances that you'll need it are quite low, because the tank starts looking filthy way before the nitrates reach critical, while the
ammonia and
nitrites simply don't appear unless you do something very, very wrong. I have tested my water a few times when my fish get sick etc, but it never showed anything wrong with it. And as far as I see in my local aquarium groups, this is an extremely popular opinion. Many even go as far as saying tests are useless even for the beginners, but there I disagree - while cycling it is a very handy tool to have.
The biggest fail I had in this hobby was actually before I really was in it, and not entirely my fault. I worked as a lab assistant in my university's zoology department. It had several tanks - a big Paku fish tank, a planted
guppy tank, and an abomination of a tank where 3
axolotls were living in, idk, 10 gallons if I'm being optimistic. Anyway, I was told to feed the tanks and to wash the filters once a week. I had no idea about the nitrogen cycle, or that it's something I should look it up. So being thorough at my work, I always washed the filters with hot water. It may not be a coincidence that a Paku died half a year into my care. Also looking back that tank was seriously underfiltered, because it only had a measly internal filter, and that Paku was huge. I also have never seen anyone doing any water changes, didn't even know that was a necessity, I wonder if I just missed it, because it should have looked filthier than it did... Axolotls also died, but that was because they chewed each others legs off. Guppies did pretty well, I guess the plants and the gravel took care of the nitrogen cycle. I'm still puzzled how a zoology department of all places could have been so bad at fishkeeping and didn't bother to explain it the basics.