30 Gallon Tank All guppies at water surface?

[cowboykidd]

New to fish keeping other than bettas, but I've done a decent amount of research. I have a 30 gallon with 3 black mollies and 3 white guppies. 0 ammonia and nitrites, nitrates at 10, PH of 7.6, water temp of 75. The tank is not live planted and is fully cycled.

The mollies were picking on each other so, following suggestion, I decided to add more fish. I added three guppies and funnily enough it seemed to stop the aggressive behavior of the mollies. However, the guppies have been acting odd pretty much since I got them a few days ago, all floating or swimming around the surface of the water. I read that this could be due to low oxygen in the tank but I honestly doubt it, as I have a waterfall filter that provides lots of surface agitation and I of course have no problem with overstocking. I tried doing a big water change yesterday night as I heard that would be something to help with oxygen level, but there was no change in behavior at all.

The mollies are acting perfectly happy and healthy by contrast, swimming around all areas of the tank. One of the guppies will occasionally leave the top of the tank and lay at the bottom instead. Overall, very strange behavior.

Any advice is appreciated. Thanks in advance!

 

[StarGirl]

I would try a air stone or something anyway, its worth a try, your water seems fine. The Mollies could be being jerks too. Have they chased them at all?

 

[cowboykidd]

I would try a air stone or something anyway, its worth a try, your water seems fine. The Mollies could be being jerks too. Have they chased them at all?

I will see about an air stone. I haven't seen the mollies mess with them one bit, surprisingly.