Erratic swimming

[Crazyhermitcrab]

Yesterday I bought a shoal of 3 green emreld Cory cats. They have been swimming weird..... Like darting and not staying near bottom.
The tank is a planted 36 gallon, with a sand bottom. And it's fully cycled.

[cfosgate]

That's normal behavior for all Corys. They are exercising LOL. Corys will often run up and down the tank sometimes gulping air at the surface. When they are excited or nervous the will dart around a lot, especially when you come up to the glass.

[twiddlemuffin]

I agree, corys are playful little things.