The short answer to this question is a definite “no”, you’re betta fish isn’t bored, at least not in the way you or I think of boredom. However, more needs to be said depending on the reason you have come to ask yourself this question.
Possible Reasons for a Betta to Seem Bored and Lonely
I can think of three possible reasons that brought you to this question. So let's briefly look into each of them.
1. A Move to a Larger Tank
You have recently moved your Betta from a smaller tank (hopefully no smaller than 2.5 gallons or 10 - 12 litres to begin with) to a larger tank, preferably a minimum of 5 gallons (20 litres) or more. Looking at your betta in this larger tank, it may seem that he is all alone with all the extra room to move around. But if this is the sole reason for your question, then you have nothing to worry about because you just like most people and me back in the day are projecting human feelings and emotions onto your pet betta. In fact, the betta is going to be super excited to have a larger territory to itself.
2. It Just Looks Sad/Depressed
To some the betta fish looks sad all the time and it probably has to do with the bettas lips, it does seem like they are frowning. But, again, this is an innocent assumption and I would have to repeat myself and say that these are just projections and the frown is absolutely nothing to take note of, it is just the anatomy of the fish. If this is something you hadn't noticed before I am so sorry that I brought this to your attention.
3. A Change in Behavior
If you’ve noticed your betta behave differently all of a sudden it most likely has to do with its environment. It could be just about anything right from the water parameters, too harsh of a light and not enough shady/hiding spots, high flow rates from your filter or low temperatures. This is an issue you would have to look into separately and is out of scope of this particular article.
If you do not find any issues with the environment, yet continue to notice a sort of sedentary lifestyle, you may want to try changing the aquascape a bit to pique interest, adding a moss ball or a ping pong ball which could make the fish inquisitive or better yet, hold up a mirror about once a day.
When the betta sees itself in the mirror it thinks that there’s another fish approaching its territory and begins flaring up to show dominance and compete with the intruder. Once you take away the mirror (only do this for short period of time, else it will stress the fish out) your fish thinks it has won and can get back to feeling proud of itself, if that is something a betta feels.
Nevertheless, it would be pleased in its own way to have defended its territory and it then has a reason to maintain the fancy tail and fins which make it seem bigger than the competition. Tail biting is a whole different topic of discussion, but in my opinion a sense of competition (the mirror) every now and then is incentive to stop chewing off its own tail.
Do We Know for Certain?
With all this said, the best we can do as hobby aquarists is mimic their natural environment and we cannot tell with certainty if they are in fact lonely or not. We just know that they do not like company in close quarters. This is similar to their behavior in the wild.
Even though the betta has been selectively bred for generations (with a focus on coloring and appearance) they continue to exhibit the desire to have their own territory. In a small tank this translates to them being alone. While we touch upon this subject, you may be interested in my guide on betta tankmates (work in progress).
A Fun Thing to Do - Training Your Betta to Limbo!
I must say that I have personally never done it, but I know of a friend (from the Fishlore forums) who has done it. He has used the R2 fish School set to have fun training his Betta fish do the limbo. Here is a discussion on the topic on the bettafish forums. It just makes feeding time a bit more interesting on the days you are feeding dried and not live food. This won’t make your Betta feel any more bored, because I doubt it is bored in the first place. But it definitely makes your time spent with it a lot more fun, probably also for the fish. You definitely do not need to buy this kit, you could easily come up with ideas of your own, just an idea that popped to mind that I thought of sharing while writing this article.
I found two videos on Youtube, one is of a trained Betta and the other of one in training. The first is just 360p, but is fun to watch, nonetheless.
In conclusion, I hope this article and the attached resources have helped set your mind at ease. It is quite normal for us to look at the lone betta and put ourselves in its place. However, moving it to a community tank or adding some "friends" to its tank may do more harm than good. I would once again suggest that you take a look at my betta tankmates guide before you choose to add any living creatures to your betta tank. Your betta may be alone, but it's not lonely, it's happy :)