Nitrite And Ammonia Levels

Can I ask what your pH is? If you haven't got a tester, take a sample of tank water (not tapwater) to a fish shop and ask them to test it - and get them to write it down. The reason is that ammonia is more toxic at high pH and nitrite at low pH. And there are things you can do. But until you know your pH carry on with the water changes.

Ammonia exists in two forms in our tanks, and one form is a lot more toxic than the other. The two are ammonia (very toxic) and ammonium (a lot less toxic). The amount of each depends on the pH of the water and on the temperature. The higher the pH and temperature, the more of it is in the toxic ammonia form. The ammonia test kits we can buy measure the two forms combined so we can't tell how much of the total is ammonia and how much is ammonium.
Once I know you have your pH and temperature I can give you a link to a calculator. Fill in the numbers and it'll tell you how much is ammonia out of the total. Then you'll know just how much of the toxic form you have, and you'll be able to tailor your water changes accordingly.



Nitrite is easier. Your only fish are platies, and they are salt tolerant. You can use salt to counteract the effects of the nitrite in your tank; ordinary table salt is fine as the amount you need is only small. There is a calculation involved.

First you need the volume of water in the tank. This won't be the same as the total volume of the tank as the filter, decor etc take up some of that volume. Assume the amount of water in the tank is 85% of the total tank volume. Then you need the nitrite level.


The calculation:
Work out 85% of the total tank volume to get the water volume - use litres.

Multiply the nitrite reading by 10
Multiply that by the water volume you calculated above
Multiply that answer by 1.5

The result is the amount of salt in milligrams to add to the tank. Don't add it directly, remove a bit of water from the tank, dissolve the salt in that then pour slowly into the tank.
If you'd find it easier, tell me the nitrite reading next time you test and the amount of water in your tank, and I'll do the calculation for you.

Continue to monitor both ammonia and nitrite. If nitrite goes up, add more salt, but only for the extra amount of nitrite - if it goes up from 0.25 to 1.0, add enough for 0.75.
If you need to do a water change because of the ammonia level, don't add any more salt. Yes you will remove salt during the water change but you'll also remove nitrite. Only add more salt if the nitrite reading goes up.

Once your cycle is finished and both ammonia and nitrite are zero, you'll get rid of the salt by your maintenance water changes.



Don't worry about stressing the fish with water changes, swimming in toxic water is more stressing. You can even do a 95% water change. Provided you add dechlorinator and warm the new water to the same temperature as the tank water, the fish won't come to harm.
Until we know your pH and can use that calculator, you need to get your ammonia reading down below 0.25.













For anyone who wants to know what is behind that salt calculation:
It is actually chloride that counteracts nitrite, and salt is sodium chloride.
The amount of chloride needed to detoxify nitrite is 10 times the amount of nitrite. A nitrite reading of 2ppm (ie 2mg/l) needs 2 x 10 = 20mg chloride per litre. That is part one of the calculation.
The second part is working out how much chloride for the volume of the tank.
The third part - salt is sodium chloride. It is one third sodium, two thirds chloride. Multiplying by 1.5 gives the amount of salt that contains the amount of chloride you need.

Hi Richard,

I have a 18" x 10" tank, so just under 30 litres.

I only have two platys at the mo (although if George, my male has anything to do with it, it will soon be more!!! )  I was feeding them one flake each twice a day and they were not eating it all so a lot of it was sitting on the bottom.  I didn't feed them today until just now when I gave them literally four freeze dried Daphnia which they ate quite quickly.

I have learnt that I have to keep an eye on Peppa, my female, as she is a pig (no pun intended!!) and will chase George away and eat as much as possible in as shorter space of time as she can!!!!

I wonder if it is worth me adding something like Tetra Safe Start as well as doing the water changes and I will definitely add the salt as suggested by Sue when I've checked my PH.

FC

Missed the bit about safe start.

From what I understand, that tells you to not do any water changes and to let the levels get quite high. I'm not sure what I'd do. If you use safe start it might help, but not doing water changes could harm the fish. I would be inclined to wait until you know your pH then you can find out just how much of your ammonia is in the toxic form.

Tip for freeze dried live food - put a bit of tank water in a small pot and soak the food for a few minutes before giving it to the fish. Freeze dried food can sometimes rehydrate and swell up inside the fish, especially greedy ones that gobble it up quickly.

Small fish tanks are a problem when it comes to stocking. I have two 18" w x 10"d x 10.5" h, one is my quarantine tank, the other used to be my betta's tank till I noticed I'd managed to crush a corner so bought him a new tank. They both hold 24 litres of water.

Small tanks are better understocked as if things go wrong, they go badly wrong very quickly. They are also awkward to stock because they are short, and even tiny fish often need a longer tank because they are fast swimmers. And most tiny fish are shoaling fish, so you need at least six of the same species.
I can give you a list of fish suitable for a tank this size, but some are for hard water and some for soft, you need to choose from those that suit your water. You can find out if you have hard or soft water from your water supplier's website, though it might take a bit of searching. Does your kettle fur up, does your showerhead gets lots of limescale? These indicate hard water. If you don't have them your water is probably soft. You would also need to check the temps they need as this does vary from species to species.

Soft to medium water:
Fish of the Boraras genus x 6
ember tetras x 6 - these are deep orange red when they've settled in, I have some
Microdevario kubotai x6 - I have some of these as well
Norman's lampeye, Aplocheilichthys normani x6
Sundadanio axelrodi - very soft water only

Hard water:
Danio erythromicron x6
endlers male only in this size tank

Both:
celestial pearl danios aka galaxy rasboras x6
Aphyosemion striatum a pair.
scarlet badis tricky to feed; a pair or 1 male with several females
One of the dwarf cories habrosus or pygmy or hastatus x6

And of course Siamese fighting fish.


If you didn't have the platies, in a tank this size, I would go for maybe 8 of one of the above shoaling species or perhaps 6 of a mid water swimmer plus 6 of a dwarf cory species. Or 6 of a mid water swimmer and cherry shrimp. That's all.
Or one siamese fighting fish, on his own (or maybe with a snail)

In my 24 inch long, 50 litre tank, I have 9 Sundadanios, 8 pygmy cories and an unknown number of cherry shrimps, and I consider that to be a bit overstocked.

With the API ammonia tester, a lot of people have problems distinguishing between the 0 and 0.25colours, so your 0.5 may not be quite as bad as you thought.

Here is the ammonia calculator Leave the first box set at NH(NH3 + NH4), type 0.5 into the ammonia measurement box, set salinity to zero, type in 7.5 for pH, and whatever your temperature is in the temp box. Then click calculate on the right hand side. The figure you want is the lower of the two boxes, NH3 concentration.
If that box shows 0.02 or lower, that is safe even for the most sensitive fish, and anything below 0.05 is fine for most fish. If the box shows above 0.05 (and yes I do mean 0.05) then you need to do a water change.

That's good, your fish should be fine with that.

Dear Idiot Fishkeeper With A Small Tank 

Sorry to hear things are stressful. One way to relieve the stress would be to go into both those LFS and beat the cr@p out of the staff who gave you that advice. I find that very theraputic when stress levels build up.

Keep doing those water changes.... you must keep the ammonia as low as possible. The useful bugglies live in the filter media (and some in the gravel etc), they're most definitely not free swimmers. There will be enough ammonia being produced and moving through the filters with your platys pooing like only platies can.

Hope this helps the stress levels....... after the random acts of violence in the fish shops, of course.

Hi fishcake.  Sorry to see it looks like you've been poorly advised by your local fish shops! After my time here I take what fish shops tell me with a pinch of salt and come back here to check the facts! Sue is the guru for all things cycling related and got me and my little tank through my fish less cycle.  Unfortunately I've heard small tanks are actually much harder work than larger tanks in the cycling and keeping your tank happy! Still mine has fingers crossed settled down again now after my city move!