Bubble Nests!!!

One of the more unexpected odd little quirks about male betta fish is when you look into their tank one day, and there’s a little collection of bubbles at the surface, usually collected around a leaf or an object sticking out of the water.

These are called ‘bubble nests’! The good news is that bubble nests are a good sign, they mean that your betta is happy and healthy!

So what is a bubble nest? Well, they’re called nests because male bettas build them as part of the mating process – a female betta will judge a male on the quality of his nest and his general appearance. It seems like a surprisingly cute thing for a fish known for its aggression to do, but bettas are actually quite caring dads!

Using their saliva, a male betta will create a little grouping of air bubbles like this:

Their intention is that once the male and female mate, the eggs will be laid into this little nest to keep them all together and afloat. The male then looks after the nest, and if any of the little fish eggs falls out, he’ll even go and retrieve them and gently place them back in the nest.

If you put a male and a female within sight of each other, a happy and healthy male will start to build a bubble nest, hoping to build something so impressive that she thinks that he’s an appropriate mate. On the other side of things – if the female is unimpressed with the nest, sometimes she will even destroy it, prompting him to make another (hopefully – sometimes I imagine that the male is pretty annoyed about this…).

But if you only have a male alone, why is he making a nest? Well, the answer is instinct really – some males will build nests when they’re happy and healthy, others don’t have that habit without a female. It’s a good sign though because a male who is unhappy or unhealthy won’t feel up to mating and therefore won’t build a nest.

So nests are a good sign! They can also be various shapes and styles, depending on the fish. I have fish with various different habits – Fury likes to build long lines of bubbles rather than a gathering, and Apollo likes to build almost towers of the things, that are a centimetre high from the surface of the water.

Neither of them were feeling bubbly today so I can’t get a photo (annoying since Apollo’s was pretty impressive yesterday), but Aries was feeling nesty and you can see the start of one above him below. He likes a scatter gun approach, so they end up quite sparse and wide ranging.

Basically it’s all good news though if you find a little bubble nest at the surface of your tank! I found that mine respond particularly well to live food – I fed them some blood worms recently and nests started popping up all over the place, so that’s their way of telling me they really enjoyed it!