I had a 2ft tank fill with ammonia previously, I did several water changes, but within a day the ammonia was spiking again. I saved a few of the Guppies by moving them to a biube. No matter what I tried the rest of the fish died as the ammonia levels kept jumping. I thought this was something to do with the Java fern and got rid of it out of the tank cleaned and have it set up, but empty.

So on to the biube. One of the fish died, (leaving a female and two males). I changed 1/2 the water, made sure the tank was clean and changed the filter. Since then I have been replacing 1/4 to 1/3 of the water weekly and am making sure that the tank is clean, The filter has been in for a month.

Today I notice that one of the males has died! I have made sure the tank is clean, rinsed the sponge of the filter in tank water and am going through the process of changing the water again.

I am thinking that I must be over feeding? I can't think of anything else I could have done, (I put anti-stress anti-chlorine stuff in the water and leave it over night before I, remove water then slowly add fresh back over the several hours-or even a couple of days.) I put only a very small pinch of food (tetra pro crisps) once a day, (perhaps 4/5 of the small round things). I do feed them every day though, so should I be doing every other day? Is this the cause or is there something else I could be doing wrong?

Your help would be very much appreciated, it has been a very annoying and distressing time over the last several months that this has gone on. I was wanting to step up to a 4ft tank or even just get a couple more fish, but until I can discover the route of this problem, I don't want to put any more fish at risk.

Hi, sorry to hear you're having so much difficulty.

Firstly, post your tank water readings here so we can advise regarding your stocking. It would also be beneficial if you were to test your tap water (after letting it sit for 24hrs) too.

Ammonia:
NitrIte:
NitrAte:
PH:
GH:
KH:



It sounds to me like you are unaware of the nitrogen cycle. The reason you're experiencing Ammonia spikes is because you have no beneficial bacteria living inside it. This bacteria convert Ammonia into NitrIte, NitrIte into a less harmful end product, NitrAte.

'cycling' a tank is the process of establishing the beneficial bacteria.

If you can, return the fish back to the local fish shop and begin your 'fishless cycle'.

There's plenty of advice here

Any questions just ask.

I can do a check later tonight on the tank water, as well as tap water, as I was preparing to do a small water change when this struck.

I do have a vague understanding, reading articles etc., of tank cycling. I did set up this Biube properly before I introduced the fish, (luckily I was setting up the Biube when my original tank had a problem). I am a little more vague on keeping the tank cycled once it is setup - I always thought it was a matter of not letting plants decay, not overfeeding, regular water changes and not adding more than a couple of fish. This is how I kept the last tank for a couple of years, seemingly quite healthy, until things went pear shaped.

The Biube is a 35L tank and I had three guppies, (now two), which should easily be okay.

I am amazed that I am having problems, as I am actually trying to do things correctly, the 2ft tank came from a friend who used to keep guppies, but hardly bothered looking after them - in fact before they gave the stuff away their main tank was full of algie, it was like a forest - the tank was next to a window = there were many fry and mature fish and they seemed to be living quite happily, although I'm sure that tank was also well overstocked!

I will also test the water in the other tank as I have actually been cycling it, so maybe I should move them if that water is okay..........Anyway I'll be back with the results later, thanks for helping.

So I have finished testing.....

Ammonia: In both tanks is 0
Nitrite: In both tanks is 0
Nitrate: Dont have a tester for that.......
PH: Water & both tanks are pH 6.0

These two I have never tested for before, so am a little wary of the results.

GH: I am not a 100% sure about the result of this test. The first time I tested I thought it was 5, I tried again later and it turned straight away, (a very pale green), so I will have to try again.......
KH: 7, I believe.

Nil ammonia and nitrite is good

Unfortunately a pH of 6 though, is far too acidic for guppies (they generally need more alkanine and harder water) which was probably the cause of death, given enduring an ammonia spike.

Fishkeepers in the North do generally have softer more acidic water so this needs to be buffered if you wish to keep fish suited to differenet water. The other issue is that with a tank pH of 6, this can cause a cycle to 'crash' as the bacteria struggle to cope in the lower readings. This could account for the ammonia issues you were seeing with the main tank.

What's your tap water pH when first drawn v leaving it for a day?

Ideally you need to raise this to about 6.5 just to avoid a crash (and over 7 though ideally given the fish you have if you wish to continue keeping this species) and monitor weekly when you do the water changes. As with all pH changes though they should be done very slowly to avoid pH in the fish - think over a week or two, not overnight. A little bit of Bicarb of Soda will help, or you can use crushed coral shell of remineralised powders.

Fresh water drawn for tank water changes is likely to fall to 6 after 24 hours too, so consider running it a day before you need it, let it fall to it's normal pH status and then buffer up just before you need it. Stops tank water pH yo-yo which is also harmful.

The 35 litre will be OK for now just as an emergency tank but ideally the larger tank needs to be made fit asap so the fish can move back. Keep dosing the main tank with an ammonia source each day, i.e. fish food/Homebase ammonia to about 3 or 4ppm each day to ensure that tank stays cycled in the interim. Without the fish poop and ammonia the fish produce, the bacteria in that filter will die otherwise.

Hope that helps but any questions, fire away

Okay, I hadn't considered the pH of the water as the culprit.....My tap water is testing a little higher ~6.4, I think, although I'm not the best at matching the colours.

I actually only have two small tanks, both 35L. All I can do is slowly treat the tank with the fish in place. As for the treatment.....adding Bicarb of Soda to the tank to make the water more Alkaline seems like a plan, but how much are we talking for a 35L tank and how frequently is slow enough not to harm the fish?

Of course, from now on I will be testing the water weekly, and keeping a close eye on the pH, now that I know it as an issue. thanks

I have mixed 1 teaspoon full of bicarb in some aquarium water and added it back, (in the empty aquarium, btw!), after about 15mins I tested pH and it was at 6.8 - formally 6.0, so I may have over done it. (As the tank was empty I just put the mixture right back, but I suppose there is a better method to very slowly add it to the tank over time.)

I will wait a few hours to make sure the solution is properly dispersed and test again. The amount of water is roughly the same in both tanks, so this will give me an indication of how little I need to add.

The more help you can offer the better, as I'm not over confident doing this.

Hi Sem

Possibly a bit too much Bicarb of Soda but given the tank you added it to is empty, no harm done

Can you confirm if you dosing this empty tank with an ammonia source whilst empty to keep the filter bacteria alive in the interim?

The amount of bicarb you need to add is dependent on several factors, mainly volume of tank, existing pH and KH but think smaller amounts to start with. For example to raise what was my trop tank (180 litres) from a pH of 6 to 6.4/6.6ish, I only needed a semi heaped spoonful or so. Easier to add much smaller amounts - think tip of a teaspoon or so to start with - wait 10 mins or so then test, then add a bit more if needed etc etc. If fish are in situ and you overdo it, only water changes remove.

You'll soon get more comfortable with the likely amount needed after a few trial runs.

I think Fishlady may have some king of whizzy spreadsheet or something that's a bit more scientific than my approach, but gently, gently

Well I took an 8th tsp and put it in a lid then took a very small amount of that, (I was going to add it over a couple of days). I then took out some tank water and mixed it with the tiny amount of bicarb and slowly dripped it back into the tank.

After it had finished, I waited a while then tested...... ~6.4 ..... there is a definite light green to the result although some yellowness is maybe present, so perhaps not 6.4, but not 6.0 either. I feel like I should leave it until I do my next water change to add a little more, just to be on the safe side. At least its heading in the right direction!

So am I right in thinking that the change is permanent, until then? Once I do the water change it will be different, but until then I dont need to worry?

I should be adding bicarb to the clean water first to get it to roughly the same as the tank then adding it? Then I can slowly add a little more bicarb.......and repeat over the next few weeks until i get the tank to 7.0. OR would you make the fresh water slightly higher and add it slowly so when it dilutes with the tank water it raises the whole tank by a small amount?.....

Anyhoo, thanks for the advice,

I would do it the second way. So if tank is at 6 and the eventual aim is 7 I would start by doing 25% changes with pH adjusted to 6.5 in the change water. After a few changes (do one a day) the tank will be at 6.5 so from then I would continue doing 25% changes daily with the change water at 7 until the tank is also at 7. At that point simply adjust change water to pH 7 every time you do a water change.

The actual calculation for how much bicarb is needed is quite complicated because the pH changes relative to the increase in kH, logarithmically. What this means is that if the water has no kH at all a very small amount of bicarb will cause quite a large shift in both kH and pH. However, when water already has some kH, the amount of bicarb needed to effect a similar degree of change increases.

The best way for you to do this in practice is by adding a little and testing as V said, especially in as you're working with a very small volume of water where any change can be greatly magnified.

The net result though is that you will find you need more bicarb to get from pH 6.5 to 7 than you do for the initial increase from 6 to 6.5.

Regarding the permanence of the change: no it isn't permanent. The carbonates you've added will be used up by the nitrifying bacteria as they process ammonia > nitrite > nitrate. How fast this happens depends on how much ammonia is being produced by the tank stock which is why even with good modern filtration we are still subject to stock limits and regular partial water changes. What you need to aim for is a balance where pH remains stable between water changes, but that may mean doing partial changes more frequently than once a week depending on bioload and pH level required for the stock in question.