Neon Dwarf Gourami Acting Very Weird

[bennett418]

I need some advice, one of my gouramis is going mad i think? it is swimming about in bursts very fast (not all the time), he is not being bullied at all

and appears to be building like a bubble nest??? he sucks air from surface and goes to corner of tank and blows bubbles upwards so that they rest on underside of glass....why!?!?!? no females in with him

help please!!

 

[my fat fish]

mine went thru a stage of this should be okay eventually