Whats going wrong?

[Aitch]

Hi all
I'm hoping you can help, as my fish keep dying for no apparent reason and I'm beginning to think I should just give up.
My husband and I have had a 92 litre tropical freshwater tank for nearly a year now and did all the right things to set it up before adding the fish. When we added the fish we did it gradually (no more than 5 at a time), left them floating on the top in the bags for half an hour and then after they'd been introduced to the tank left the light off for a couple of hours. But nearly every time we've added new fish we lose one within 48 hours. Symptoms are usually gasping at the top, which I've read is a sign of stress, but is there anything I can do about it? (I know there is no problem with the oxygen level in the water, as it is always just one individual fish and I have plenty of plants and an air stone) I do a 20% water change and filter clean every week and check the ph regularly, so I can't think of anything else that could be wrong.
Also, even after the first 48 hours, I don't seem to keep the fish for very long. I mean, what is the average life expectancy of a tropical fish? Am I just expecting them to live longer than is natural, and if not, what can cause them to die off one by one with no apparent symptoms? At the moment I have 2 plecs, 4 mollies, 6 neons and 2 silver sharks. So far I've lost 1 molly, 1 silver shark, 4 neons, 2 peppered corys, 1 plec, 3 guppies and a siamese fighter.
My husband is now talking of getting a larger tank, but I don't want to continue at all if I can't find out why the fish are dying with such frequency. Please help!

 

[Alien Anna]

The most common reason for losing new fish is a nitrite or ammonia spike. Please follow the link in my sig and read my article on New Tank Syndrome. You will notice I mention problems with an established tank - it is possible you will find the solution to your problem in that list.

Get back to us if you have any further questions or if this doesn't explain your problems.

 

[fish&chips]

how big is 90 litres sorry not to good with that

just doesnt seem much to me as i got 50 gallon and well 3.7874 ltr to uk gall= hmm lol around 25 gallon ??

2 ft by 12 " ?

this may be a reason there dieing i think you may have to many fwishys

the silver shark aka BALA SHARK grows 1 half ft long lol you say 2 silver sharks
= 3 fr between them a plec they can be 10 inch cant they
so 2 them thats another ft and half

between the 3 fish that 4 and half foot full grown but they may not have enough room keeping them happy causing stress and only dieing 1 at time not together due to high spikes by to many fish -)-)
and if signs of nitrite nitrate ph would be normal just over crowded casuing unhappyness ..the thing with the going to top gasping that deffo lack of oxygen
these big fish need lot room lot air maybe .....

this isnt a dig at you but just Maybe im new myself but have spent a long time studying sharks and the bala silver trio shark is my fav
but sold very cheap in uk 5 pounds and easerly bought not knowing how big they will become

i wouldnt have 3 ballas and 3 plecs and neons guppies and fighter
the siemese fighter in MY OHO is can be very aggresive will most likely kill another male female if in tank and can be teritoral towards other smaller fish and the silver is non aggresive its so piece full

 

[platypus]

Hi,

Firstly welcome

As AA says, new tank syndrome could have caused all your woes. Although your tank has been established for a while, any fish who survived the process of 'cycling' could end up permanently sickly and susceptible to disease

A few other things that it may be worth considering:

1. Do you have tester kits for ammonia and nitrite? These will be far more harmful to your fish than pH levels. If you don't have these I would definitely recommend you invest.

2. At times your tank may have been overstocked, which might have caused high ammonia levels and caused the high levels of fish death. The general rule is 1" of fully grown fish to 1 gallon of water (sorry, I don't know what this is in litres, but you'll find at the top of the beginners forum there is a good currency converter)

3. What is the temperature of your tank? If it is too high then the oxygen levels will be reduced, even with an airstone and live plants

4. When you clean your tank, do you clean the gravel also? And when you say you do a filter clean, what do you mean by this? All the beneficial bacteria that keeps your water clean is housed in the filter and gravel, so if you clean these too thoroughly you will be wiping the bacteria out, meaning your tank is constantly cycling and recycling. When you clean your filter media, make sure you do so in tank water and not tap water, and don't clean all the gravel in one go.

5. Other than that, do your fish show any sign of disease? Any markings on their scales/gills? Redness or whiteness?

Good luck with your problem, hopefully we will get you through it!

 

[Aitch]

Thanks for your advice so far - heres a bit of extra info. In proper english the tank is 20 gallons! We do have tester kits for ammonia and nitrite and both tests come out fine. I really don't think overstocking is a problem, as we've never had more than about 15 fish in the tank at any one time, and 10 of those were neon tetras. The silver sharks and plecs are only about 2 inches long, and we've never had more than 2 of each in the tank at the same time. The temp of the tank is 24/26. You may be onto something with cleaning the filter and gravel too thoroughly, although wouldn't this show up in the ammonia and nitrite tests? Mostly they show no signs of disease, although the last one to die - a silver molly - did have a red patch behind her fin on one side. Not sure if this was caused by others bullying her while she was dying though - why do they always get sick at night so you wake up to a dead fish and there's nothing you can do?!
Is my husband right in thinking that if we get a larger tank and an external filter, we'll have less problems?

 

[fish&chips]

yes very correct i have found the bigger the tank the easyer to keep i have 4ft 50 gallon

and well your going to HAVE TO if you want keep those silvers there gonna get very big and reallllll fast the thing is and ive just fallen out with my bro over this is just because they look smal are they happy in small tank is it 2 ft
if so they can grow and fill the tank on there own 1 fish
and i would give that a 8-10 120-189 gallons of water they need alot of room

just becuase they fit and they swim dont make them happy

im not having ago pls pls dontthink im being rude just letting you know these neeed more room

also i have a fluval 203 external filter cleans my tanks within 30 mins if that

i do gravel clean and clean plants get real cloudy then goes extreamly fast
it also has 3 filter chamber so i guess can old more bacteria

 

[Alien Anna]

You may be onto something with cleaning the filter and gravel too thoroughly, although wouldn't this show up in the ammonia and nitrite tests? Mostly they show no signs of disease, although the last one to die - a silver molly - did have a red patch behind her fin on one side. Not sure if this was caused by others bullying her while she was dying though - why do they always get sick at night so you wake up to a dead fish and there's nothing you can do?!
Is my husband right in thinking that if we get a larger tank and an external filter, we'll have less problems?

Hi, I definitely think you could do with a bigger tank as those itty-bitty 2 inch fish will grow (a common pleco, for instance, can grow to 2.5 feet long). However, it is worth taking things slowly and figuring out what went wrong anyway.

It is entirely possible that following cleaning of the filter you killed off your beneficial bacteria and had an ammonia spike or nitrite spike. Since the gravel would have contained plenty of beneficial bacteria the cleaned filter would not doubt re-colonise within a day or so but ammonia is very toxic and could have already done the damage by then. Also, you could have had a problem with chlorine or chloramine unless you used dechlorinator on the water used to clean the filter (I'm assuming you cleaned it in tap water).

A red patch on the gills is often associated with nitrite poisoning.

Also, what is your nitrate level? Although people don't generally worry about nitrate as levels below 50 ppm are not thought toxic, my experience is that above 25 ppm can be a problem for some fish (perhaps fish weakened by the cycling process) and with our grotty tap water it is not uncommon to find levels of 75ppm out of the tap.

Do you have live plants? If so that would explain why you have lower oxygen levels at night. Try putting an air-stone in just at night.

You are somewhat over-stocked for a 20 gallon and am I right in thinking your tank is a hex tank? If so, you may have inadequate surface area to absorb the oxygen required for so many fish. In which case, your husband's suggestion is probably right that a bigger tank with a better filter would help a lot. What I'm concerned about is that your silver sharks grow to 11" long and need to be in a school ideally (6-8 fish). They also require a lot of swimming space. Your plecos are going to grow far too big pretty rapidly once your water quality improves and your mollies are likely to both grow (up to 3.5" long) and breed. If you want to keep these fish, you are going to need an enormous tank - at least a 6 footer. That may not be a problem for you - I know some people get big fish so they've got a deliberate "excuse" to upgrade, but just be aware. A 4 ft tank isn't going to solve the problem for long.

 

[fish&chips]

i dont mean to repeat but as this is a strong point of mine (the shark)
please read this caruflly and i have taking it from a webporifle

General Information:
The Bala shark is a large, fast-swimming, schooling fish--you want to make sure that you have room for a group of them. They can get close to a foot long, but even at smaller sizes they really appreciate having lots of lateral swimming space.

i would even like to correct this they grow to 1 half foot long i have seen 1 at almost 2 foot

they should my op must be in groups of 4 in NO min then a 4ft tank
then when grown into 6-8 foot

if you have 4 i would say 8-by 3 or 4 ft high

dont think im moaning please just that you really should move them and not mny ppl will say it BLUNT but somtimes you need to so sorry again if you have found me rude

also if you have hex like anna says and sounds that way it means its long and oxygen isnt to good for any fish that get big

and i really have to agree i think you clean it to much
when i bought new fish i got leaflet saying about being carefull with clean and not to enthusiastic (-spelling sorry but many ppl think its dirty and clean but its actualy not

(how do you clean your filter is it sponge type (under tap water or do you use the water when making water change from the tank as this is the right method it cleans it but also keep most the bateria i think im not to sure

 

[Inchworm]

Hi Aitch and welcome to the forum!

Others have gone into the chemistry issue with your tank so let me raise another possibility as regards the new fish you introduce into your tank.

Where do you buy your fish? Is it a good reputable fish shop? Or do you buy them from a chain store that may or may not take proper care of them? I bring this up because fish do not always show symptoms of weakness or impending illness until they are home. Then the stress of being transfered to different water might be too much for them.

Even under the best of circumstances, at a good lfs, if the fish have just been shipped in and transfered to their tanks, then sold and transfered to your tank, you might have problems. This is quite stressful and it is not that unusual to lose fish in the process no matter how good your water. If your water is less than perfect the problem is compounded.

Also, please remember that when you are transporting them they can take a chill or overheat quickly in the little bags of water from the shop. This too will stress them and can be avoided with care.

Good luck with your tank. You will get things worked out and then you can help others here at the forum.