elaphe

warrreagl,
I would add to actinic by saying that having people you trust in the pet stores is vital not only for them to steer you in the right direction in terms of equipment, but also for the right advice on keeping our little guys healthy and happy. I can't count how many times I have heard people tell me "but the guy in the other store told me they wouldn't eat each other". The marine hobby is a "knowledge is power" type hobby. Not only does the salesman have to know the equipment and point you in the right direction, that person should know where the fish are caught (most marine animals are wild caught), what it would eat in the wild, what it is eating right now (if it is eating!) and how long the store has had it in captivity. It is definitely a buyer beware hobby. Even if you do find that one person that you trust, don't let it stop you from doing the research yourself and ask questions. The dumbest question is the one you don't ask!
It sucks to loose a pet that you watch grow up. I had a golden puffer named "Spud" that I (reluctantly!) sold to a very nice family who spared no expense to make sure he had a great home to swim in. Unfortunately, they didn't realize that painting the walls in the same room would have dire effects. Paint fumes were absorbed by the water and Spud died of internal organ failure.

JStrider,

Not that I would ever disagree with good friend actinic , I must add that adding sarassa comets is the "safe" bet. Because of the size of most barrel ponds, the the number of goldfish you can safely keep would be limited. Not that having 3-4 goldfish wouldn't be a bad idea. I would personally be a little bit more daring and think along the idea of having large livebearers like sailfin mollies or even medium-sized gourami species like kissing fish or moonlight gouramis. This would give you a variety of species that could co-exist and you can create a pond that most wouldn't even think about having. Plant up the barrel with irrises and reed plants like dwarf papyris or dwarf cyperus. Dwarf water lettuce would be an ideal floating plant. Check out the local gardening centers for the specialized pots used for ponds and the specialized bedding material. I'm sure that actinic would have some thoughts as to other plant species and have better insight as to planting them - right actinic? Just remember that water flow and filtration is key regardless of what species of fish you want to keep. This sometimes becomes challenging in a barrel!

LoganSnake,

I agree with actinic. It could have been a toxic shock of some kind.

Whenever I am confronted with a mystery, I try to find answers to the following questions:

Was there any changes in the feeding/husbandry habits in the two weeks just prior to the unexplained fish loss?

Was the care of the fish shared by yourself and another? Did they do something different?

Was there a change of the brand of food? Like most pets, they only eat what they like. The rest just sits in the aquarium and rots.

Do you use a tap water conditioner (if you use a municipal water source)? Bottled water?

Was there a water change done just prior to the "darting" behaviour?

For better or worse, 6 months is not bad for owning a betta. Yes, the average life of a betta could be a year with 2 to 5 years not being uncommon. Just like us, the better the food, shelter and living environment will help will longer life. Unfortunately, some of use die young for a variety of reasons. Fish too are not immune to chance/genetics/disease.

For long term success, having a larger volume of water will definitely benefit the health of the fish - regardless of species. It will help with a slower build-up of the concentration of toxins and help to stabilize water chemistry over a longer period of time.

If you want the chemistry, you have to ask actinic - he's the biochemist in the pairing!

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