Hardy Fish

[haleem8777]

I am after what fish you believe to be hardy, as in it wont die easily. as i have been having problems with fish dying easily after water changes i have brought so i was wondering what fish is very hardy so i can look to keep that in my 20 gallon.

 

[fluttermoth]

What fish have you had?
 
It would be better to find out what causing the fish deaths, as it's likely that, whatever it is, it will affect 'hardy' fish as well.
 
You really shouldn't be losing fish because of water changes; how, exactly, are you doing them? Are you using a dechlorinator (and of so, which one?) and warming the new water? What sort of percentage water changes have you been doing? Have you tested the pH in the tank and from the tap (after standing for 24 hours)? Do you know the hardness of your water?

 

[eaglesaquarium]

Lots of good questions from flutter there...
 
When fish die for seemingly no reason, its important to investigate what the reason is so that more don't suffer the same fate.  Just putting more fish in the tank without trying to fix the problem usually means more of the same.
 
 
What symptoms do the fish have before they die?  Do they show signs of stress before or directly after the water change?  How long after the change do the fish die?
 
 
The more information we have, the more realistic for us to determine the cause of the previous deaths, and more importantly prevent them for the future.

 

[Ch4rlie]

Fluttermoth and EaglesAquarium are both asking perfectly good questions which should be answered with as much information as you can possibly provide. No such thing as too much information really.
 
Difficult  help you if we do not have any information to go on with.
 
I have couple more questions that may also help us determine a cause for you and how to sort things out for future.
 
Is your tank cycled? 
if so, how did you cycle the tank?
 
Water parameter readings? ph, ammonia, nitrite and nitrate
What test kit are you using? liquid or test dip strips.

 

[haleem8777]

Firstly the water changes i do them by taking out the water from the tank which ranges from 20% and 25% then i get new water allow it to rest  then i add dechlorinater tends to be tetra brand, then i add the water to the tank and put in a little more dechlorinater, dont no why just seems it has to be done.when the water is added the fish just seem slightly paler then they colour up later on, no signs of illness at all.
 
The tank has been cycled for about 6 months, cant exactly remember how i cycled it but i know the tank was without fish for a month at the start, just the water being filtrated. There was no problems with fish deaths for 4 and a half months and then the stock of rummynose i had died so waited about a month  and in those weeks i changed half the filter media as i thought that could be the problem.then the tank was left for two weeks while i asked for stocking ideas on the forum. i decided on threadfin rainbow fish and i got 7 last weekend and by wednesday the 11th they were all dead with no signs of illness.
 
finally the water over the past weeks i have not had a water test kit, anyway i tend to do my water changes on a friday and on a saturday i take a sample to the petshop and he  test everything for me. He has a liquid test kit.there was no problem with ammonia, nitrite and nitrate but over the last month and a bit since the rummys died  the ph fluctuated from 6 to 7,5 . the last to weeks when i took the water to the shop we focused on ph and it remained constant between a value of 6.5 to 7 ( cant remember the exact) so i decided i could get fish so i brought the threadfin rainbow fish. They were brought on Saturday and on Monday i did a small water change. and 2 days after that they were dead.

 

[Ch4rlie]

I would recommend you get a water testing kit, a liquid kit really. 
 
This may be the first step to do, testing tap water, then test your tank water before water change and test after water change.
 
This may provide some clues.
 
Sorry for your losses BTW 

 

[eaglesaquarium]

Leaving the tank empty with no fish AND changing half the filter media, more than likely drastically reduced the amount of bacteria in the tank, and probably caused a mini (or full) recycling of the tank. 
 
Further, you never mentioned how you temp matched the water, nor what temp the tank water is compared to the new water being added...  Temperature shock could be the reason that the fish lose their color when the new water is added, and then color up again later (probably after both the temp has risen due to the tank heater and due to their bodies adjusting).  Rummys are notoriously good at indicating their unhappiness with the water parameters by losing their color. 
 
It seems as though you are also adding far too much dechlorinator.  That's probably not a big issue, but something to note.  At the very least, you could save money by ONLY adding the dechlorinator once and not again to the tank later.

 

[haleem8777]

thank you for the reply , so the cause of death could be a mini cycle happening seem realistic, so does the temperature change.
i use thermometer to measure the water temperature before i add it.When i had the rummy they never did lose the colour in the nose only the threadfins did, i as guessing they are slightly delicate.
 
so where do a go from here.
*get a test kit
and ... 

 

[fluttermoth]

..some ammonia and do a proper fishless cycle.

 

[Ch4rlie]

here's a link to help give you ideas of suitable ammonia available.
 
http/www.fishforums.net/index.php?/topic/427161-ammonia-and-bacteria-starter-sources/

 

[eaglesaquarium]

And then always make sure that the temp matches on your water changes, at least within a degree or two. 

 

[l_l_l]

Great info shared here.
There is one thing that I'm wondering..
Do you use the buckets that hold your fish water for anything else?

 

[Dreamer03]

I was about to ask same thing, what was used to do the water changes. I hope things go better and fish stop dying.

 

[haleem8777]

The bucket i use,  is never used for anything other than fish stuff, what i mean if occasionally i use it to store aquarium equipment and plants. One thing slip my mind was that there is still 1 rummynose in the tank, not all of them died.so what shall i do with it?
 

..some ammonia and do a proper fishless cycle.

 so do i have to cycle my tank again?

 

[KirkyArcher]

The fish are dying after a you've done a water change that you've overdosed with dechlorinator, Now I'm no Inspector Morse, Detective Columbo, or for that matter a Miss Marple.....
(many brands of water conditioner do contain chemicals that are harmful to aquatic life if overdosed) nowhere on the packaging of Tetra Aquasafe does it say overdosing is recommended and actually states half dosing is OK, and even on the Q&A page there is a reply saying that overdosing can kill your fish!
You probably are still cycled, get water tested to confirm this, and follow instructions on the additives you put in amongst your fish.