My betta, the iFish, and I have shared office space for two years, including a major relocation. Last week I finally got the stuff together and cleaned his tank after about 6 months. I run a filter, so that duration works just fine. However, I left a sustained release feeder for Science Online. Then I forgot and left the light on one weekend. By Monday, we had algae.
Today he demonstrated his utter happiness by spending the morning building a bubble nest. He has done this before, but never one so large!
I began to worry about his intentions, so I decided to read a bit about this behavior. Did he have ulterior motives toward me? He does occasionally puff up and "threaten" those who enter my office. According to the folks at NippyFish:
This nest building behavior is instinctual for male bettas and it is not necessary to have a female present to observe your betta building his nest. Most males will blow bubbles but the rate and size of the nest seems to depend on the individual male and possibly, other factors like age, health and water parameters.
Some males will frequently blow bubbles and you may find new nests on a weekly or even daily basis. Others may only blow a few nests a year. Healthy males tend to blow nests more often so if you see one consider it a good sign that your betta is happy and healthy.
The NippyFish link also includes some higher quality bubble nest photos. I also find it fun that the male betta is so integral to child-rearing. He builds the nest, gathers eggs into it after spawning, guards it, and returns any eggs that fall out. Turns out the fierce Siamese fighting fish is a gentle parent, at least until the fry mature.
Of course, we all get that urge to kill our teenagers.