Bubbles

[madcracked]

 I know bubbles can be a sign of some medicens in tank but I haven't put anything in.all parameters seem to be normal. Wondering if this is a fish bubble nest?. Congo tetras, opaline guramis, neon tetras, hillstream loaches, yellow rainbowfish ramshorn snails, cory doras, otocinlous. Non that I'm aware of that do this. Any thoughts

[Biotope Biologist]

Gouramis make bubble nests. That appears to be a bubble nest. Doesn’t necessarily mean they are breeding, sometimes they will just do it.

[JoeQ]

That looks like a gourami bubble nest. Heres one mine made, notice the similarities.

[Lennie]

I had male bettas building bubble nest randomly. But never had a gourami building bubble nest "for fun". Is that also a thing?

My males have the breeding dress but never build bubble nest, unless they really wanna go for the breeding I guess.

 

Opaline gouramis are usually agressive as they are. With some breeding action involved, I bet they would get quite agressive

[Biotope Biologist]

I had the opaline counterparts, gold gouramis in college. Granted the tank was eclectic reject bin from my work. But they were quite content just chasing eachother around. I had 1 male 4 female. They lived with a goldfish, sunfish,BN pleco, chinese algae eater and a male convict cichlid. 
 

But yeah they were constantly making bubble nests in the corners and doing that beautiful gourami mating dance. No babies ever came of it though.