To the average betta keeper, bubblenesting is all but synonymous with bettas. If you like me, visit betta specific forums, you will see that there is something strangely compelling about that white foam of bubbles.
As a keeper and breeder of predominately bubblenesting bettas, it has been interesting to study the differences in the size, shape and location of each nest.
Some males are so blasé about the whole process that they do nothing more than string a few bubbles together at the front of the tank. More meticulous males however, can work on their nests for days at a time. They place each bubble with razor's-edge precision, and don't allow the often impatient female to get more than a glimpse of the nest until it is complete.
There are some males that have absolutely no reservations about building their nests out in plain view. Unfortunately for us breeders, most males will usually hide themselves and their nest away, requiring a gymnastics performance worthy of the Olympics if one wants to check on things.
Film canisters are useful in that you can easily move them to get a look at the nest and any eggs or fry it might contain without overly upsetting the ma. Being submerged bubblenesters, coccina complex species seem to have a particular preference for using canisters as nesting sites. However, not all of my males have been lured in by the siren call of that innocuous black cylinder.
Below, I have included some photos of my males and their nests, showing how even in one fish room, there can be quite a lot of variation.
Hailing from Melbourne, Australia, I currently keep and breed a number of species from the coccina complex.