What Killed My Betta Fish?

[AnonymousMuggle]

Hi all,
 
Firstly, this is my first post on this forum, so I hope this is the correct place I should be posting this question. I'm completely new to owning a pet, let alone a fish, so forgive me if I sound super foolish!
 
So here's the deal: We got a blue half-moon betta fish just over a month ago at the request of my 12-year-old brother. He wanted a pet, but our parents didn't trust us with a 'real pet' (a cat) so we decided to get a fish, thinking it'd be less hassle. We also travel quite a bit and it'd be hard to find a place for our cat to stay if we went on holiday. 
 
Anyway, this week the house was empty because the family was out camping in the mountains and I work at a residential summer camp. So we put a ticker-feeder-thingy that had worked before and dispenses 2-3 pellets a day. I just came home to find a murky tank with a rotten black fish at the bottom and I was really wondering what caused him to die. He was alone for 5 days and nights and a number of things could have caused his demise. 
 
First of all, the feeder was faulty and wasn't turning and there was no food for all the 5 days. So I just assumed that it had starved. But then I looked online and found that bettas could usually go for a week without food, so maybe it wasn't that. 
 
What I'm thinking is that our setup is grossly inadequate. We have a 1/2 gallon tank (tiny!) that is unheated and unfiltered. I think that the ammonia, NO2, and/or NO3 levels got sky high and it died from poisoning. Could that be? We don't have a testing kit.
 
The reason I'm asking is that ever since we got our fish, I've been obsessing about it online and telling my parents we have to upgrade his setup. But they were adamant that the guy at the store said bettas were supposed to live in puddles and that 1/2 gal would do. So now that our fish has died, I really want to get to the root of the problem so that when or if we ever get a new fish, we'll be better prepared. 
 
If I'm to convince my parents, I kind of need good solid evidence that the fish died either from a toxic environment or from temperature. From the following info, could any of you tell me how he died?
 
The water was gross when I got home and he was at the bottom, completely black and really soft, so he must have died earlier this week. The last time his water was changed (50%) was 5 days ago, 10 August. That was also the last time he was fed. Where we live, it gets to about 19 ºC at night right by the thermostat and maybe 25-26 ºC at midday. The water shouldn't experience quite that much fluctuation, as it's not right by a window or anything and water doesn't heat or cool as fast as air if I'm not wrong.
 
Could any of you determine what the cause of death was? I really hope it didn't just die of starvation because that would be sad and I'd be really mad at whoever made the stupid automatic feeder. In any case, the death was caused by negligence on our part and I really want to make it right by determining what we need to do better if we get another fish. 
 
Thanks for reading my whole rant and helping me out. Also, have you any tips regarding keeping a fish while still being able to travel? We travel frequently, up to 3 weeks at a time in some cases, so if that just isn't feasible while still taking care of a fish then we should probably just forget this hobby!
 
Marcel

 

[Bluesand1313]

Alright, it sounds to me like he died of poor water conditions.
Bettas are tropical fish, which means they need a heater at 24 to 27C to thrive. The ideal tank size for a betta splendin would be a 5gal.
He could have also died of starvation, as they can fast for 1-2 days, but I've never heard of going almost a week without food.
And especially with a tank that small, with no filter or heater, and it hasn't been changed in 5 days? Honestly, calling for disaster. In a tank that small, the water would have to be changed daily.

I feel like maybe these websites will help explain more;

Here is a website in which you DO NOT want to follow its advice. I'm showing you this so if your parents say "but it said this on the internet!" You can show them this: not all websites carry correct information. THIS IS NOT A GOOD WEBSITE! it's wrong.
http/micbow.hubpages.com/hub/Betta_Fish

And here, are good websites. This first one has FIVE PAGES of myths and facts about bettas.
http/bettacare101.com/mythvsreality/
http/www.instructables.com/id/How-to-Properly-Care-for-a-Betta-Fish/step3/Basic-Betta-Info/
This wikihow is actually very correct!
http/m.wikihow.com/Take-Care-of-a-Betta-Fish

 

[the_lock_man]

Hi Marcel, welcome to the forum.
 
I think you are right, in that it was almost certainly ammonia poisoning that killed your fish, the problem being made far worse by living in such a tiny tank. You don't mention any form of filtration for the tank, so I would assume that there was none. In such a small tank, the ammonia concentration will have built up exceptionally quickly.
 
Unfortunately, many pet store employees put profit before fish welfare - I would suspect that he believed that your parents wanted the smallest tank possible, and if he tried to insist upon something bigger, they would refuse and he would lose the sale.
 
What he should have sold you is an aquarium at least 10 times bigger than that, a 5 gallon is the absolute minimum for a betta (most fish need much bigger than that), and the tank must have a filter. The filter will build up two colonies of bacteria, one which converts the ammonia into nitrite, and another which converts that nitrite into nitrate.
 
I do not believe that your fish starved, fish can certainly go for much longer than a week without feeding - I disagree completely with Bluesand on that point I am away for 7 nights in a week's time, and I haven't asked anyone to feed my fish for me.

 

[Bluesand1313]

I stand corrected, and you did a much better job explaining than me. It's been quite a while since I've given any advice so I might be a little rusty c:

 

[AnonymousMuggle]

Thanks a lot for your prompt replies! It seems this death has put my parents off this hobby, so we're not getting another fish after all, but I am now quite interested and I might get myself a betta fish for when I move out to Singapore next year. I'll definitely be sure to get a 5g tank with a filter, not sure I need a heater in Singapore! Oh yeah, and a testing kit of some kind so I'll actually know if something's wrong with the water.

Anyway, really appreciate the help!

Marcel