Gourami Bubble Nest - bubbles immediately dissipate - why?

[dovesong]

Good afternoon! I have a strange problem and I can't seem to learn anything about it online, so I'm posting here in the hopes that someone might have an idea.

I have a pair of breeding Gourami (Opaline) who have successfully spawned many times over the past year. Lately, when my male tries to build a bubble nest, the bubbles vanish within seconds of him blowing them and he seems unable to build a bubble nest. This problem began in November, and I don't think I had made any changes that would have impacted him or the water quality. Since this started, I've tried to adjust the water - balancing the pH to a 7.0, using a water softener to lower the hardness, but nothing has seemed to help.

Today, they have apparently given up and are spawning anyway, without a nest! Argh! Does anyone have any suggestions? I just did a water change with a water conditioner but without the pH buffer or any aquarium salt; here are my current water conditions: 78 degrees, pH 6.5, 0 KH and GH. My nitrates and nitrites also test to 0, as does the salinity of my water. (I figure I can always add things but it's harder to take things out, so I kept my additives to a minimum with this water change.)

Thoughts? Ideas? Anyone ever have this problem before?

 

[dovesong]

Quick update - this afternoon I added Riccia to the tank and placed some of the smaller loose pieces in the "feeding ring" that I use for my Gourmis to build a bubble nest in. I went out this evening and when I came home, still no bubble nest but there are tons of eggs floating among the Riccia leaves in the feeding ring! I'll try to take some pictures tomorrow, if anyone's interested. Whoever heard of Gourami's spawning without a bubble nest? I really hope someone can shed some light on this for me!

 

[joy13]

The only thing I can think of is Indian almond leaves I have noticed with my bettas their nests last a lot longer when I put some Atison't betta spa in their water. I don't breed bettas but use it when I notice one isn't feeling up to their usually self.