With regards to the "bubble"....be warned!
My son had one a couple years ago. Started out fine, then the bubbles appeared......VERY shortly thereafter, the STINK came!!

The only way to describe this smell is that of a Porta-Potty, left in the middle of a cow pasture, on the hottest day in July.

A quick bit of research tells us that the "bubbles" are actually the male beta, making a bubble nest, trying to convince the female to come lay eggs in his nest. I am not sure whether the stench comes WITH the bubbles or if they "go bad" after a couple of days. All I can tell you is if you see them, get them out of there ASAP! Eventually, I guess he gave up and did stop making the bubble nest.

Until then, buy clothespins!!