I didn't see any kind of thread on this, so I thought I'd write up a little care sheet for anyone who's interested. Since they're so common a pet. There seems to be a lot of misinformation. If there's one animal I know better than my snakes, it's my bettas.
I'd really like to clear up a lot of misconceptions about these beautiful and personable fish.
Standard tank keeping practices apply, weekly water changes, cycle your tank before hand, don't over stock your tank, have enough filtration for your tank acclimate new fish, Etc.
AqAdvisor - Intelligent Freshwater Tropical Fish Aquarium Stocking Calculator and Aquarium Tank/Filter Advisor is a good place to figure out what your tank/filtration capacity is. I won't go too much into explaining the beneficial bacteria/ammonia cycles and such, since it applies to any fish, and should be standard knowledge keeping any fish.
If you need to read about cycling your tank:
Aqadvisor.com - Cycling a new tank
The Tank.
This is often a highly debated subject, many large retail stores claim that these fish live in small muddy puddles, and actually prefer smaller spaces, to justify the selling of those tiny little cube/novelty tanks. This is completely false. A betta's natural habitat is rice patty fields which hold tens of thousands of gallons of water. The puddles they refer to happen during the dry season and still usually contain at least 10 gallons of water, but still many of the fish die while in these puddles for the season.
A bare
minimum of 5 gallons is recommended for these fish, anything bigger is even better. In my years of betta keeping I've used everything from bowls to vases, up to a 20 gallon tank, and I can say that they do thrive with the larger spaces. Better colors, more activity, they just seem all around happier and healthier with more room. They're a very active fish, and should be given as much room as can be allowed. They'll thank you for it. There's nothing sadder than a betta just lying down on the bottom/just floating at the top of a bowl/tiny tank all day. .
Breeders often use 1 gallon or smaller jars, or fish barracks to save space due to the hundreds of fry produced from a single breeding, but this is far from ideal. daily water changes are a must in these set ups (for the jars), and they often have entire rooms dedicated to their fish, the whole room being heated to a betta's required temps. This set up is difficult to manage and shouldn't even be considered if you just have a few as pets. (why would you, I wonder?)
You'll also want to make sure you have a lid/hood for what ever tank you may be using, These guys are jumpers. They also require access to air, their labyrinth organ enables them to breathe from the surface, making airstones unnecessary, but if not given access to the surface of the water they can and will drown. I've seen it happen on multiple occasions from my friend's fish, and very sadly one of my own who got trapped in a decoration. (I freed him before he passed, but it was immediately obvious that he suffered some kind of brain damage, he dashed to the surface and gulped as much as air as he could for several minutes, he was swimming backwards and in circles the whole time. He passed that night. The decoration went straight into the garbage.)
Heating
We take such care that our reptiles are kept at appropriate temperatures, why not also our fish? Most common problem I see with bettas comes from them not being kept at appropriate temperatures. These are tropical fish and need to be kept around 78-82 degrees. They can "live" with lower temperatures, but it makes them much more susceptible to illness, they're significantly less active, their colors dull and they're just completely miserable. Tank heaters are mandatory. This is another reason to keep your fish in a larger tank, a tank less than 5 gallons runs the risk of being over heated due to too large of a heater, and unfortunately I've yet to find/hear of any reliable heaters for any tank smaller.
Most tank heaters come with a built in thermostat, but you still need to keep any eye on them with a reliable thermometer. Not the stick on glass ones, (They only read the temperature of the glass itself, not the water.) but either a digital thermometer meant for fish tanks, or heck, even one of those cheap glass ones with the suction cups work nicely as well.
Filters
Filters like heaters are mandatory for your betta. Filter, and the filter media is highly valuable space for all of those wonderful beneficial bacteria you want to keep in your tank. It is true that bettas generally don't like a strong current, especially the bettas with the longer fin types like; veiltails, halfmoons, and crown tails. However Plakats and females who have the shorter tails/fins seem to do just fine with a normal "Hang on the back" type filter. The longer finned types can adapt to HOB filters as well but they really do prefer a slower current. I'm a fan of sponge filters. While they're not the prettiest, they're simple, cheap, effective, and produce a fairly slow current. You can very cheaply make your own, or If you're not the DIY type, petsmart usually has some for around 7$ for the smaller ones.
DIY Sponge filter:
Nick's Aquarium: DIY Sponge Filter
Food
Feeding them is fairly simple, they're by nature insectivores. And their diet should reflect that. A generally accepted feeding schedule is 6 days of food (1 feeding a day or 2-3 a day with the portions divided accordingly.) with 1 day a week of fasting to help with digestion. Some even recommend using one feeding day to give them a mushy pea, an unsalted, cooked pea without the shell. Broken up into bite size pieces. Bettas like variety in their food, so when you can mix it up a little! What should make up the majority of their diet is often argued as well, I recommend researching this further for your own fish, if you'd like. I'm merely posting what has and has not worked for me.
First off flaked food... I've never had a betta actually eat flakes before, They're not that well balanced nutritionally, they're dry, easy to overfeed with and just plain unappealing to the fish and myself.
Pellets are popular, my favorite brand is Hikari pellet food for Bettas. Care should be given when feeding pellets however since they're dried and will expand when they absorb water. (Feeding rule of thumb! Your betta's stomach is only as big as his eye! don't over feed or you're likely to get swim bladder disorder!) Usually 4-5 pellets a day will suffice for most bettas. I'd recommend this as a base diet for your average betta.
Freeze dried food is also popular, baby brineshrimp and blood worms being the most common. They're incredibly dry like the pellets, so use caution not to over feed while using these. These are best fed as treats in my experience, even while being careful not to over feed I did see more cases of swim bladder disorder while feeding just freeze dried food.
Frozen food is wonderful as well, you'll see just frozen blood worms in most big box stores, and while the bettas think they're tasty blood worms are pretty high in fat content, so they're not recommended as the sole food source.
Live food is by far my favorite so far. While there's several types of live food you can feed your betta (mosquito larvae, brown worms, blood worms, baby brine shrimp.) Flightless fruit flies are probably the easiest to come by, and make up the majority of my own fishes diet and they couldn't be happier. You have to be careful when feeding live food though. Some bettas will eat
all of the live food in their tanks until nothing is left. Even to the point of killing themselves doing so. I personally haven't had this happen, but have heard of it, so very carefully limit what your betta will be eating. There is also some risk involved when it comes to parasites. I've heard of this most commonly in the live worms, but I've yet to see any of my fish afflicted by parasites from my fruit flies, but that's still remains to be seen.
Cohabitation
Stating the obvious yes, but two or more male bettas should not be in the same tank at any given time regardless of its size. They're called fighting fish for a reason, and while they wont fight to the death (just until one surrenders and is chased off.) There is no real running away from each other in a tank, even if it is an exceptionally large one. Males and females shouldn't be paired together either except for breeding, for the same reasons. They wont tolerate one another unless they want to breed. Sorority tanks are a whole other story on the other hand and require at least 20 gallon tank and at least 7 females to spread out aggression with lots of hiding places. Even then not all females are fit for living with other females. Some just wont put up with it. I wouldn't recommend a beginner try this. Its incredibly risky and you could very easily loose all of them due to an disease outbreak caused by one girl being stressed.
A single betta living in a community tank is a completely different story. Most bettas are quite happy to live peacefully with other species of smaller tropical fish, granted that they don't have long flowing and colorful fins. Careful not to place them with other nippy fish however, their fins are easy targets and they tend to get picked on. Best thing to do is get fish that tend to stay in different levels of the tank. Bettas like to stay up towards the top, so you'd get fish that prefer the middle or bottom level of the tank. Cory cats tend to do very well with them, since they're bottom feeders. Not all bettas are suited for the community tank lifestyle however. Some are simply too aggressive to be kept with other fish. I used to have a female who lived happily (I thought) with 5 cory cats until she quite randomly decided that she was done with them and killed two, taking both of their eyes, and leaving another with only one eye, in the span of two days. The third is still alive to this day thankfully 2 years later. (Re-named captain bronze beard.) he is now living with a much more peaceful male. The female was moved to her own tank, and passed about 6 months ago. This was an odd exception however, She was the only fish I'd had have issues with living in a community. Still keep an eye on your betta when he/she is first introduced after being quarantined and acclimated, (mandatory as with any other fish.) a little flaring and chasing is normal in a new environment, but if he keeps it up after a few days or if you find any dead/injured fish that where healthy before hand remove him immediately.
All in all they're a fun, but simple fish to keep. I've spent a lot of time over the past 10 years just watching them explore and interact with their tank mates and me, flaring up as they show off. They seem to be capable of even recognizing the difference between people. I've had one who was completely in love with my mother, flashing his fins for her whenever she came up to him, but would ignore anyone else. I've even had one who oddly enough clicked. Along with the many others I've shared the years with. I hope that's not too long of a read, I tried not to ramble as I like to do, but I tried to explain everything the best I could. I love my betta's quite dearly, I've learned a lot from them in my life and I hope this post is of help to someone.
If I missed anything or if you've any questions/need clarifying feel free ask or let me know. I've spent 3 hours typing this already and my brain is a little shot at the moment.