Any fish experts in the house?

[13m]

One of our children bought a tank and cold water fish recently. The fish are Danios and platys. We followed the instructions of the shop to the letter and have been back 6-7 times to have the water tested. Evidently we had "new tank syndrome".

The Platys have not been happy, swimming near the bottom, and tonight one died. Cue much wailing from the young owner.

We're scheduled to go back to have the water tested again tomorrow. Last time the nitrite reading was high.

I presume that the shop (Pets At Home) know what they are doing, however does anyone have any tips please? We don't want the trauma of another fatality - and the other Platy looks wobbly.

The Danios have been fine throughout by the way.

[Turn7]

Personally speaking :

PAH are dire in terms of aquatic knowledge.

I wouldnt have either of those species in an unheated tank.

Has anyone mentioned tank cycling to you ?

Whats the size and volume of the tank ?

Were all fish introduced after tank filled with water ?

How many fish ?

[13m]

Turn7 said:

Personally speaking :

PAH are dire in terms of aquatic knowledge.

I wouldnt have either of those species in an unheated tank.

Has anyone mentioned tank cycling to you ?

Whats the size and volume of the tank ?

Were all fish introduced after tank filled with water ?

How many fish ?

Tank cycling - you mean change 50% water, then 20% then 20% etc? If so yes.

Tank 21L I believe.

The Danios were introduced first and have thrived. Then the Platys.

There were 4 - two of each. Now one Platy only.

[AlexC1981]

Tank cycling refers to the nitrogen cycle. Fish produce ammonia. Bacteria grow in the filter and consume the ammonia and excrete nitrite. A different type of bacteria grows and consumes the nitrite and excretes nitrate, which is nowhere near as toxic as the first two chemicals. You have to do a weekly part-water change to get rid of the nitrate. It takes weeks for the right bacteria to grow so you have a stable cycle and zero ammonia and nitrite levels.

I assume your tank has a pump and filter? Do you know anyone with tank who might be able to donate some of their existing filter media? You can jump start the cycle by using donated media.

Alternatively get some Tetra Safe Start. It contains bacteria that usually takes ages to grow. It is one of the few products of its type that actually does help to get your tank started quicker. You can buy it at PAH. Don't add Tetra Safe Start within 24 hours of using a dechorinator or any sort of ammonia removal treatment as it will prevent TSS from working.

[13m]

AlexC1981 said:

Tank cycling refers to the nitrogen cycle. Fish produce ammonia. Bacteria grow in the filter and consume the ammonia and excrete nitrite. A different type of bacteria grows and consumes the nitrite and excretes nitrate, which is nowhere near as toxic as the first two chemicals. You have to do a weekly part-water change to get rid of the nitrate. It takes weeks for the right bacteria to grow so you have a stable cycle and zero ammonia and nitrite levels.

I assume your tank has a pump and filter? Do you know anyone with tank who might be able to donate some of their existing filter media? You can jump start the cycle by using donated media.

Alternatively get some Tetra Safe Start. It contains bacteria that usually takes ages to grow. It is one of the few products of its type that actually does help to get your tank started quicker. You can buy it at PAH. Don't add Tetra Safe Start within 24 hours of using a dechorinator or any sort of ammonia removal treatment as it will prevent TSS from working.

OK yes this has been explained. As I said, the last test showed high nitrites. Presumably that will self correct in time but we don't want to lose any more fish in the meantime.

[InductionRoar]

Most good aquatic centres will give you some of their water from a well established tank (which is the correct PH) - this may settle it down sufficiently.

Put plenty of plants in there too.

Good luck.

[13m]

InductionRoar said:

Most good aquatic centres will give you some of their water from a well established tank (which is the correct PH) - this may settle it down sufficiently.

Put plenty of plants in there too.

Good luck.

Thank you.

[Spitfire2]

13m said:

One of our children bought a tank and cold water fish recently. The fish are Danios and platys. We followed the instructions of the shop to the letter and have been back 6-7 times to have the water tested. Evidently we had "new tank syndrome".

The Platys have not been happy, swimming near the bottom, and tonight one died. Cue much wailing from the young owner.

We're scheduled to go back to have the water tested again tomorrow. Last time the nitrite reading was high.

I presume that the shop (Pets At Home) know what they are doing, however does anyone have any tips please? We don't want the trauma of another fatality - and the other Platy looks wobbly.

The Danios have been fine throughout by the way.

Don't know where you got the idea that Danios and Platys were cold water fish. Get a heater and filter and they will likely all be happier.

[Turn7]

Nitrites and Ammonia are lethal to fish in tiny doses.

You need to allow the tank and filter to establish its bacterialogical filtration.

Safestart can help, but do not add anymore fish.

The problem with these tiny tanks is that there is such a small amount of water, the parameters can swing wildly with any change in water condition.

Get yourself an API test kit and check for Nitrate, Nitrite and Ammonia weekly.

Use a good dechlorinator - Seachem Safe for example.

[AlexC1981]

Spitfire2 said:

Don't know where you got the idea that Danios and Platys were cold water fish. Get a heater and filter and they will likely all be happier.

I think they prefer the cooler side of tropical (sub-tropical?). They would probably be ok in the height of summer in an unheated tank, but not over a UK winter unless you keep your thermostat turned right up 24/7.

By the way OP, before you add fresh (dechlorinated) water, let it come to room temperature first. And get that TSS!

[Wombat3]

13m said:

AlexC1981 said:

Tank cycling refers to the nitrogen cycle. Fish produce ammonia. Bacteria grow in the filter and consume the ammonia and excrete nitrite. A different type of bacteria grows and consumes the nitrite and excretes nitrate, which is nowhere near as toxic as the first two chemicals. You have to do a weekly part-water change to get rid of the nitrate. It takes weeks for the right bacteria to grow so you have a stable cycle and zero ammonia and nitrite levels.

I assume your tank has a pump and filter? Do you know anyone with tank who might be able to donate some of their existing filter media? You can jump start the cycle by using donated media.

Alternatively get some Tetra Safe Start. It contains bacteria that usually takes ages to grow. It is one of the few products of its type that actually does help to get your tank started quicker. You can buy it at PAH. Don't add Tetra Safe Start within 24 hours of using a dechorinator or any sort of ammonia removal treatment as it will prevent TSS from working.

OK yes this has been explained. As I said, the last test showed high nitrites. Presumably that will self correct in time but we don't want to lose any more fish in the meantime.

It will self correct but in the meantime you can keep the level down to non lethal levels by changing a quarter of the water in the tank (which is more than you'd normally change).

Fish/food waste gives off ammonia.

As has been said you need two colonies of bacteria to grow & deal with Ammonia/nitrites. The first one turns ammonia into Nitrites, the second turns nitrites into Nitrates (which are harmless unless the quantities are huge). The fact that you have high nitrites indicates that you have the ammonia eating bacteria but not yet the nitrite eating variety in sufficient quantity yet.

To reduce the levels of nitrites in the meantime you need to change some water. As above I would change out 25% & then test again & see where you are at. If necessary do the same again a day later. You will find the high levels will persist but then pretty much disappear overnight (which indicates you have your second set of bacteria). You may also get a bloom in the tank (water goes cloudy) for a few days. Don't worry about it, it will clear.

Also slow down on feeding the fish. Most common mistake is over feeding. Food doesn't get eaten (or if it does fish poop a lot). Poop and/or rotting food gives off ammonia (see nitrogen cycle above). Feed sparingly, fish won't starve if you don't feed them for a day or two. Its not a bad thing to put them on a 5/2 diet anyway! Hungry fish are usually healthier.

The bacteria grow all over the tank & the filter, in the gravel etc. The one thing that kills them is chlorine so you never put water straight from the tap into the tank & you never wash your filter under the tap - always in a bucket of water from the tank (or rain water is OK if you have some).

You can use straight tap water but fire it into a bucket (i.e. wide open tap) first and then leave it to sit for 24 hours. The chlorine will dissipate.

As has been said there is other stuff you can treat tap water with as well but tap water is also too cold to go straight into a small tank like that, so add a bit out the kettle to warm it up in the bucket as well.

Don't add any more fish till the nitrites come down to zero. Then add more slowly. No more than 2 a week - you need to allow the bacteria colonies to ramp up to deal with the extra load from two more pooping fish!

In that size tank you don't want more than about half a dozen anyway. As a general rule small tanks can actually be more difficult to manage than larger ones because they are more sensitive & need more regular maintenance. The key to success will be "little and often", under feed, don't over feed and keep the fish numbers below the maximum capacity. If you stuff it full of fish you will be far more likely to have problems.

Edited by Wombat3 on Thursday 11th February 23:04

[otolith]

13m said:

I presume that the shop (Pets At Home) know what they are doing

Kids with minimal training and a clipboard, in my experience. Only livestock I ever got from them was a few snails nowhere else local had in stock. Thought their questions about the tank were impertinent so when asked I listed the fish by binomial name and watched them struggle to spell them.

[pills]

Where in the country are you?

[13m]

pills said:

Where in the country are you?

Near Nottingham.

The water was tested again today - high nitrite level.

We've bought some tablets that mat help and will do another series of water changes.

[Pat101]

Hi .

sorry for not reading the whole thread but what filtration are you using??

Cheers

Pat.

[13m]

Pat101 said:

Hi .

sorry for not reading the whole thread but what filtration are you using??

Cheers

Pat.

Don't know. It's a black rectangular one bought with the tank.

We put in the balls to sort out the water and this evening the second platy, which I though was a goner, is swimming about more happily.

[robbocop33]

Surprised more people arent mentioning about the danios,they're tropical fish needing warm water!!Well at least they were when i kept them alongside my neons,siamese fighter fish,mollies etc

[13m]

robbocop33 said:

Surprised more people arent mentioning about the danios,they're tropical fish needing warm water!!Well at least they were when i kept them alongside my neons,siamese fighter fish,mollies etc

The danios are still going strong. The one remaining platy is remaining still at the bottom of the tank.

[paintman]

What temperature is your tank?
I've kept danios & consider them to be a tropical. Bit of a temperature range on the internet, but 64degF seems to be the bottom figure with low 70s advised.
Never kept platys, but seems to be the same min temp for them as well, again with low 70s advised.
I currently have a 2' cube community tank - so a mixture of fish - and keep the temp in the low 70s. The guppies - endlers - breed like, well, guppies! (BTW if you keep guppies or platys in conditions that suit you're likely to have a lot more & as they're livebearers a small inquisitive child asking you what the fish are doing to each other)
These links may be of interest:
https://www.aqua-fish.net/articles/guide-keeping-p...
http://www.thinkfish.co.uk/article/danios-and-deva...

[budgie smuggler]

13m said:

Tank cycling - you mean change 50% water, then 20% then 20% etc? If so yes.

Well that process can take 6 - 8 weeks to complete. And it's usually 50%+ water changes you need each time, not 20%.
Think about it, 20% removes only 20% of the toxins (whether ammonia or nitrite), so you're leaving 80% in there. It's going to accumulate more and more each day until the bacteria grow.

So for now:

Keep doing big water changes daily (50%+) with (ideally) temperature matched, dechlorinated ('conditioned') water.

Cut right down on feeding, just a very small amount per day. (Those fish can live several weeks with none at all in fact.)

Don't replace the dead fish for a couple of weeks.

Good luck

edit: bugger, didn't see this was already covered above. +1 on the Tetra SafeStart advice, it's a good product.

Edited by budgie smuggler on Tuesday 16th February 11:30