Odd behaviour?

[ViPz]

One of my six harlequin rasbora (the only male) keeps swimming along just under the surface of the water as if he is slurping up something or breathing, mouth open, just swimming along as if feeding, but there is nothing there to eat that I can see.

I have put some medicine in the water (Melafix) for my Betta, could he be trying to drink this up?

Thanks

 

[aqua_chem]

Probably not drinking the meds. There are two possibilities that I see.

One, you have an issue with oxygen in your tank. This can be cause by a combination of overstocking and/or poor surface agitation. Depending on your flow/filters, this may or may not be an issue.

Two, he's eating the surface scum off your tank. My platies do this all the time. If he keeps sucking on the surface and it doesn't look like he's panting at all, then that's probably what it is.