Black Mollys

[ElNino]

Hi again

I've got two black mollys in my 60L tank with stingray 15 filter.

One of the mollys has just spent the past 15 mins swimming away from the filter and then stopping, looking like its being dragged back (although towards the top of the filter) then swimming away, repeating this for 15 min.
Now he's swam away and is being normal.

Was he just playing, or is he ill?

 

[OldMan47]

It sounds like he is playing to me. I have fish play with the water from filters all the time. I think the funniest is a mature male betta that has trouble just holding his position because the filter flow in his tank is so strong. He works his way around the side of the flow path and then drops right into the flow and rides it across the tank.