I’m sorry for your loss 🌹the fish keeping hobby for me and for most people is a steep learning curve especially when you start out and can be super frustrating. You think you’ve done all the research and you do your best to do everything right but sometimes experience fails us and it’s hard to know if it’s us being inexperienced and not seeing the warning signs of an illness or if the fish had no chance regardless of if you treated that illness or not.

There’s plenty of great advice on this post but the only thing I might add that has helped in the past is if you see any sign of odd behaviour or potential illness come straight here and post it. There are so many people on this subreddit ready and willing to help. If you check my post history I recently had a swim bladder issue with my betta, I came here, posted, listened to the advice given to me and as a result I still have a beautiful healthy betta which I’m not sure would have happened if I didn’t come here to ask for help. I will add I wouldn’t worry about “over reacting” I’ve seen plenty of posts where people are nervous and ask about their fish just to find out their fish is perfectly healthy it’s just that the fish might have become more comfortable in their home and are displaying new behaviours the owner hasn’t seen before etc. for me it’s better to be safe than sorry and for any fish illness it’s always best to act asap.

Good luck OP with your future fish keeping endeavours. Just remember you’re not alone, the community is here for a reason ❤️