Advice Please

[melvinator]

 im banging my head against a wall here.
i have had 3 angel fish that 2 died 1 survived approx a month later different batch we purchased another 2 which now 3 weeks down the line they have died to i have also had 1 gourami die a neon and 1 other gourami(dwarf). they never all died at once but lost the 2 recent angel fish the neon and both gouramis within 12 days of each other. i dont use salt and i dont add any liquids to the tank i have easy balance here but i try not adding chemicals if i can help it.i have mollies (lyre tales) red tail sharks neons dwarf and big gouramis silver fin shark corydoras danios and neon. they all love their food and swim happily however they do come to surface a lot.

tank set up
5ft x2.5ft x2ft
running 2 external filters
i have water going back returning through spray bar which both joined together forcing water down which creates lots of air bubbles
i also have 2 air stones each end of tank so oxygen shouldnt be an issue
most of tank is artificial other than few real plants. as i have sand bottom and big pleccy puuls them up. (very annoying lol)

for water
amonia 0
nitrate 5
nitrite 0
ph 8
temp is 26 27 is does drop at touch and heater kicks in back to normal i do have 2 300watt on there.

any ideas please would be help as i cant see any other problems. i feed flake and 5 in 1 frozen food bloodworm etc again i leave that to defrost and get room temp before feeding.

i also apologise for lengthy message but hope this gives you all a better picture

 

[Meeresstille]

Are they all gulping air at the surface when they come up? 
The pH is the same coming from the tap? (you can test it by filling a glass and let it stand for 24 hours, then test it)
 
Do you see any spots on any of them, maybe looking like sprinkling of salt? Are they displaying "flashing" behaviour, where they seem like they are scratching themselves like they are itchy, maybe on plants, substrate or decorations?
 
Stockingwise I see a problem though if all those fish you listed are in the same tank. Angelfish often will eat fish that will fit into their mouths. I've never kept any and don't know much about them but aren't red tail sharks aggressive? Maybe there are some aggression issues, incompatibility issues you need to look into.

 

[melvinator]

no they all seem fine together i moved the neons in there as the guppies i have in seperate tank had just had babies so gave them more of a chance moving the neons. the angel fish were only small and couldnt fit other fish in their mouths only fry size. my ph is from tap yes so thats why its 8 which i didnt think would be an issue as it should be at the 7.5 mark anyway. the fish do take air in when they go to the top but with the air bubbles through the whole tank i wouldnt thought be an issue either. none have had spots etc. i have had other fish nip the dead fish but thats once they have died. with the size of the tank all the fish have plenty of room to have their own territory i even have a rock one end with bog wood above as a cave for the fish who prefer this and sand with ornaments along the rest of tank for other fish. the only fish i saw aggresive behaviour from was a rosy barb which was removed

could to much lighting be an issue or would that only effect algae growth as recently i have had all 4 lights on during day and just 1 blue and 1 white during night

 

[Meeresstille]

Gulping at the surface is a sign of them not getting enough oxygen from the water. Corydoras will come up for surface air normally anyways, but it is not normal behaviour for your other fish. 
I don't understand why the air bubbler would not help with that, and you do have a long rectangular tank, where the surface area is nice and big. The temperature may be a little warm, I would reduce it one or two degrees and see if it makes a difference. Warm water holds less oxygen, but again, with the air bubbler going, I'm not certain that the temperature is to blame. (Are you certain the temperature measurement is correct? What type of thermometer is it, the glass kind inside the tank, or the stick-on kind on the outside?)
 
Parasites sitting in the gills would also make fish come up for air, but your fish seem to be showing no signs of that either. I'm hoping someone more experienced will come by soon and help you figure this out! 

 

[Ch4rlie]

What type of test kit are  you using?
 
Just looking for any clues here, test strips are notoriously unreliable.
 
But if thats API liquid test kit then not sure whats going on, seems unusual with these results as otherwise would have said nitrite or possibly ammonia poisoning is going on.
 
Have you added anything new to the tank before these symptoms started? Live plants or decor?
 
Decor in good condition? no peeling/flaking paint or anything like that?
 
Water change routine? do you clean the filter media?
 
Sorry for all these questions as already said am just looking for any clues here.

 

[melvinator]

fish are not constantly at top but do come up in water quite often i know gouramis are supposed be high up but they all seem to do it. i have air bubbles each end and in centre. i use liquid tests for accuracy and i have both glass heaters inside the tank. again tho im sure water temp wouldnt kill i do only have stick on strip that tells me water temp but i test with hand daily whilst feeding. i also dont clean filters out to often been bout 2 months now but with water results being ok i thought they would be? as for water change i leave glass lid open by bout 4 inch so condensation evaporates and i just fill i also use water from big tank when i fill breeding tank so i know the water is cured already as i have sponge on air pump for the little tank
im just hoping i have no more deaths as i hate seeing them dead and makes me feel im not doing something right
 
i do thank u all for ur replies tho i really appreciate it

sorry forgot no new ornaments or plants have been added for bout 3 months. i had this on another tank set up i have but that was severe i lost guppies by the hour and it wiped out most of the tank but i only had strip tests then. again the water by them tests said it was ok but something was wrong after water change and allowing tank to run for few weeks it seems be ok. i feel im feeding enough etc so really am puzzled. just wasnt sure if it was down to bad luck or i was doing something wrong here