Tropical Fish help!

Hi..........we've had our tropical tank up and running now since just after christmas when the original one exploded in our living room. We have just a few guppies, zebra barb, rosy barb and tetras........all fine up to yesterday. Now the guppies are staying on the surface of the water most of the time, they haven't any fungal spots or other signs of illness!

Tested the water and all tests are fine..............any clues or suggestions?

Have only got puffers, plecs and catfish, but I may be able to help?

What'd you mean by staying near the surface? Gulping air? Upside down?

What d'you use as an air supply?

Becs

Got 3 lots of air blowing through an Elite 799 pump with 4 valves for air pipes..........no fish aren't gulping or upside down, just hovering just below the surface of the water?

Also got a Fluval 2 plus filter running......2 lots of live plants.

We have 2 lights one sun glow and the other a uv light, how often should they be on?

I've never owned your breeds, so I'm not sure if there's anything species-specific I should be telling you.

I usually try to have my lights alternating. It's never seemed to make a difference to mine how often they're on or at what times, so long as the fish get dark time too when all lights are off. I usually have a sun-glow or equivalent on for most of the day, and the UV in the evening for a couple of hours, then dark.

How do the plants look? Healthy?

How many fish have you got and what size tank?

What're you feeding?

What temp is the water at?

How much algae have you got?

D'you add any chemicals, conditioners, preventative medication etc?

We have a 20 gallon tank 31" wide x 13" wide x 16" deep, 8 tetra, 4 guppy, 4 zebra barb, 1 rosy barb.

Plants are fine, they are fed tropical flakes once a day, temp of water is 80 F and no algae at all.

We add Stress Zyme Dual Action weekly, and Nutrafin Water Conditioner when we do a part water change.

When we feed the fish, they all swim over and eat, then when the food is gone they all go back to one corner near the surface.........really strange!

Are they sitting anywhere near the outflow for the pump?

CC have pmed you

have you sprayed anthing in the room air freshners or glass cleaner or even perfume

I think all guppies do this because my sister has a tropical fish tank and everytime we visit her house her guppies are always near the surface of the water too, never thought to ask why, perhaps its just a guppy thing