My new boys Damean and Cobalt have made their first bubble nests with me!! I've only had them for 4 days too.(Damean made his like 2 days ago but I wasnt sure if it was one untill all the bubbles from the new water went away)
Usually I'll get boys who only build bubble nests if they see a lady betta for a long time. But they made one without any girls to be seen.
(at least I only showed Damean Athena to get him to flare but that was only for like 5 mins (any other of the boys I had would have to have seen her for a couple days) )
Wish my camera card would work in my computer again. Otherwise I'd have pics