Why are my tropical fish staying at the top of the tank? gulping for air?

-i have three mollies and three platys

four live plants and a filter that pumps oxygen and other benifital bacteria into the tank ( fluval u2)

ive tested the water for ph etc and all is perfect and the tank has been set up for over three months

there doesnt seem to be anything obviously wrong at all, just the fish who dart to the bottom now and again and rush to the top and stay there

any ideas?

thanks in advance :)Something is terribly wrong either in the tank or filtration.

You only have a few hours to do a good 75% water change, or the fish will die.

I would also run more air into the tank. Get some more air stones flowing, after you get that water changed out.

Could you possibly have a dead fish, that you are unaware of? some fish foods, make the water bad pretty quickly, consider that also.

Trust me, these fish will not make it much longer, unless you act asap on it.

good luckThere are some type of mollies and platys and enev guppies called "Top breathers" When I first got my guppies they were all over and I was excited that I could have them. Then they stayed to the top and I worried that I wasn't feeding them and blah blah blah until I did my reaserch and found out that it is perfectly normal.



Also to all those ppl out there that say that he doesn't have enough oxegyn in his tank, BS. There really isn't a way to even put oxegyn in the tank because there are two options, bubbler or filter. The filter is to keep the water clean and when it releases the water it will create a current, a small one but yes a current. The bubbler is designed to create waterflow for those that couldn't afford filters.



I personally don't like live plants and the matter they create but, hey, if it works for you then go with it!



I would do a 15-20 % water change just in case tho, it wont hurt.



Hope I helped!!!
please dont listen to the comment about fish not living in water there whole life( i think the first one). well i have 2 creamsicle lyretail mollies and they will do this little thing where they put there mouths to the water and start blowing bubbles. i do not know if this is exactly what yours are doing but it could be it. the filter creates a disturbance on the top of the water to allow air to get into the water. it doesnt just pump air out. i would get a bubbler. this will put some air in the tank and create more disturbance at the top of the water allowing air to get in.
uhm about that first answer... ya that is why fish have gills. they can breathe UNDERWATER!!!! CRAZY HUH?!?!?! and i would try doing a large water change and testing your ammonia, nitrites and nitrates. hope this helped
This kind of behaviour normally points to high ammonia/nitrate.



Try a large volume water change and maybe do a little maintenance on your filter.
you may have too many plants using up oxygene remove some also clean your filter every 4 weeks
I think you may have an ammonia problem.
fish can't live in water for the whole of their lives they need oxygen every now and then if they didn't they would die. :-) hope i helped