So my beta Billie died today.
I'm really sorry for your loss, SIP Billie.
Came down this morning and found her up at the top of the tank after acting a bit odd the previous day. I treated the water and found the Nitrate and Nitrite slightly higher than usual so did a partial water change. Later in the day i found her right down the bottom of the tank along by the plants and then a couple of hours later was dead. Her tummy looks a bit bloated so do you think this is the cause and if so what can cause that?
Bloating can happen for minor reasons, but when a fish is actively dying and bloats up before they die, the bloating is just a symptom, a sign of organ failure. What caused that organ failure and the death? That's much, much harder to pin down, and we'd need to quiz you a lot more on your set up and what might have contributed etc. But even then, we're not aquatic vets, we can't really run tests, so the best we can do is research as much as we can, and try to make educated guesses and attempt to diagnose and treat that way.
After death, the body can swell and look bloated as the decomp sets in as well, so might not be organ failure if she didn't pinecone before death (dropsy), could just be decomposition.
I seem to have had constant problems since starting out with initially fun rot which I tested and cured, then Popeye which I again tested and cured but now this.
Really feeling gutted and unsure why things have gone so badly. I tested the water regularly and all was fine with good readings other than those posted above from today.
I'm really sorry, and I suspect it isn't your fault. Bettas are not healthy fish now. They naturally have short lifespans, but they're also bred for qualities other than health and hardiness... only for colour and fin shape, and previously, for aggression for fish fighting.
They're being farmed in huge fish farms abroad, it's an inexpensive but very popular fish, so they're mass produced if a variety gets popular, it gets bred more and more, both by hobbyists and those fish farms, that may not have the fish in the healthiest conditions, and diseases and parasites are easily transferred to fish and/or not treated.
Bettas have those glorious big fins... but those fins are so delicate and easily torn. Even a micro-tear is enough to let bacteria or fungus to get in and take hold, causing death by a secondary infection and just too much for the weak, poorly bred fish farm betta, and it passes away.
We probably get more threads about sick and dying bettas than any other fish. I don't know that for sure, but have followed so many threads where betta keepers have done everything right, everything they possibly could to give the betta the best life, and it still dies. People breaking their hearts over them and blaming themselves, even leaving the hobby altogether because it sucked any joy out of their hobby, and they blamed themselves for the deaths.
I love bettas, but I don't think I'll ever get one for this reason. We'd be happy to give advice about other fish you could try in whatever tank you have if you want to try something other than bettas, if you're wanting to try again? Or if you want another betta, how to prepare the tank and tips to try to find healthier hobbyist bred bettas, if you like.
Again, I'm sorry for your loss.