Oh no! This makes me sad, please don't feel that way! It was clear from the way you were keeping such a close eye on your neons and the way you talked about the tank how much you cared about them, and that's 90% of the battle right there. You care and observe them carefully, and you're willing to learn and improve, so you're exactly the kind of hobbyist the aquarium hobby needs, and the kind who will take care of his fish.
But this part is wonderful
There is so much to learn in this hobby, the first year or so especially, the learning curve is almost vertical, lol. Even people who've been in the hobby their whole lives still have plenty of things they can learn, there are so many types of fish, new scientific discoveries, the hobby has also changed a lot over the last 40-50 years. As new discoveries are made, it changes the way we do things.
You're also very much not alone in following poor advice, or making mistakes! We've all done it at some point, so you're in good company
It's what you do about them that counts, and you clearly want to do the best thing for them, even if it means saying goodbye to a fish you love.
Have a measure and see whether a 20 gallon tank is possible, you'd find your fish options opening up a lot, and even mollies can get quite large as they get older. a 20 gallon would really open up your choices. I think I've seen kuhli loaches recommended as possible in a ten gallon, but for sure a 20 gallon. They need a sand substrate, and also a small group, but they're not as demanding in terms of space as many other loach species. I've never kept kuhli's so you'd need to research them. And again, dwarf chain loaches could work in a 20 gallon. A 20 gallon really doesn't take up much more space than a ten, but does make a difference for the fish, and second hand tanks come up for a sale often, so doesn't need to be an expensive purchase, and your equipment and substrate could just be transferred.
If you are able to find that water quality report for your area,
@essjay is our chemistry expert who can determine what your water hardness is. We need to know GH, KH and pH to be able to suggest potential fish. This was my mistake as a beginner. I didn't know or understand about GH, KH and pH, and ended up keeping my favourite fish in water that was much too hard for them, shortening their lifespans. I have them in softer water now, but the damage has likely already been done
But I'm still glad I learned, and got them into softer water for the remainder of their lifespan, and will be better prepared to provide the right conditions for the next ones I get.
This is one of my group, otocinclus
View attachment 115583
. I believe GH comes out at about 3 drops of the GH tester, when done one at a time. The pH was actually very close to neutral (7) if im not mistaken.
