Pregnant tetra? Weird ball on base of tank.

[Janekb]

Hi, we have a fairly new tank (3 months) with six tetras, three guppies and two Mollie as well as a couple of water snails.

One of the tetras has been acting slightly oddly in the past few days, hiding a lot and not swimming with the shoal. She looks suddenly quite fat and I wonder if she is pregnant...

There is also a large ish (about the size of a large marble) clear ball which has appeared in the bottom of the tank and I wonder if it is a nest? To describe it, it looks a bit like an aquarium ball, but we haven't used one of those since we first set the tank up and this suddenly appeared from nowhere

Any thoughts?

 

[SaraB]

Tetras don't get pregnant like guppies and mollies do. She could just be constipated.

Not sure about the ball thing, can you add a picture of it?

 

[Janekb]

Sorry, I mean ready to lay eggs rather than actually pregnant....have tried to take a picture of the ball here but it's really hard to photograph! It's just to the left under the F of the fishing sign. Is totally clear and completely spherical.

 

[SaraB]

I have no idea about the clear ball, it doesn't look like anything I've seen before.
What kind of tetra is she? Some are decently see through and you should be able to see eggs.
Is she pooping? Does it look normal? If not it could be constipated or have an internal parasite.