Why have my tropical fish died?

Question

We have a new tank and have dechlorinated the water and added bacteria and plants. The temperature is 25 degrees and we have an electric filter, an airstone and a light. We added two guppies and 12 neon tetras. All were fine until the next day when the tetras were found lodged in plants, ornaments, gravel etc. Most were dead. The few that were left alive were listless and bobbing around the tank carried by the currents - only capable of twitching. Over the course of today the two guppies have sunk to the bottom of the tank, becoming listless. They are now lying on their sides and occasionally turning upside down. Can anyone suggest why this has happened and how can I prevent it from happrning again?

100 litre tank (fish were a bit lost). Did not use detergents to clean tank.

Answer 1

You are seeming ammonia poisoning at work. The ammonia comes from the fish waste in the tank and in a mature tank is converted by bacteria in to nitrites and them to nitrates. A large water change may save your remaining fish is done quickly.

When a tank is new, it must grow the bacteria needed. I know you added bacteria, but obviously that was a bad batch and was probably dead. That's the case all too often with those bottles of bacteria. Far better not to use them at all.

Try a large water change asap to save the other fish, then get an ammonia test kit and watch the ammonia level in your tank. Do enough water changes to keep it in a safe level each day until the bacteria grow enough to take care of the ammonia. Check it daily and change as much water as needed, 10% or 75%, whatever it takes to keep the levels in a safe range.

Here's a links with even more info on the nitrogen cycle:

http://www.firsttankguide.net/cycle.php

Hope that helps

MM

Answer 2

I think the fish have died far too quickly for it to be ammonia poisoning, Did the water go cloudy and smell of Ammonia?
I would suggest the is some other factor, more likely poisoning of some type, I.e detergents heavily over dosing with bacteria culture.
I would start again if I were you. Clean everything with warm water (no soap).
Set the tank up, get the water up to temp, Leave for a week and then follow the other guys advice on the nitrogen cycle.
Do not try to cycle the tank as it is, something is wrong it's not worth the risk

Answer 3

Hi,
I think that when you totally set up a new tank you need to let the water sit in the tank for at least a week before you add any fish. You've done the right thing with the additives to the water, but it still needs to 'cycle' first.
I did the same thing. I upgraded from a small tank to a large one, and just put the fish straight over after 24hrs - and then realised i should've waited longer. Luckily they were all ok, but a couple didn't look too good for a couple of days.
What i did was
1. about a 20% water change every day for the week (but NO more than this each day),
2. added some aquarium salt - just ONCE on the FIRST day, not every day, as the salt stays in the water (but this will depend on your water as well).
3. added a general purpose "cure all" to the tank every day for a week as well.
You can get both the aquarium salt and the cure all from your pet shop - and probably ask them for advise while you are there too.
But hurry!! Your fish are only tiny little animals and wont last long if you dont get them help!
Good Luck!!

Answer 4

Do not add fish untill you have fully cycled the tank, some people will tell you to buy some hardy fish to do this but I find this cruel to the poor fish, get a bottle of ammonia and a master test kit like the API test kit for example and a medicine dropper.

Fill the tank with declorinated water and whatever decorations you wish to have, turn on the filter and turn the heater up as high as it will go, mine was in the mid 80's, do a base reading on the water for Amonia, Nitrites, Nitrates and PH and note them down, then add amonia untill you get a reading of 4-5ppm on the test kit and note how much it took to do this.

Test daily to see what the ammonia reading is. There is no use to test for anything else. Nitrite and nitrate won't be present until some ammonia has processed. Ammonia will raise your pH so no use to test it either. Once you see a drop in the ammonia, test for nitrite. There should be some present. When the ammonia drops back to about near zero (usually takes about a week), add enough to raise it back to about 3 to 4 ppm and begin testing the nitrite daily.

Every time the ammonia drops back to zero, raise it back up to 3 to 4 ppm and continue to check nitrites. The nitrite reading will go off the chart. Once the ammonia is dropping from around 4 ppm back to zero in 12 hours or less you have sufficient bacteria to handle the ammonia your fish load produces. Continue to add ammonia daily as you must feed the bacteria that have formed or they will begin to die off.

The nitrite spike will generally take about twice as long to drop to zero as did the ammonia spike. The reason for this is two-fold. First, the nitrite processing bacteria just develop slower than those that process ammonia. Second, you are adding more nitrite daily (every time you add ammonia, it is transformed into nitrite raising the level a little more) as opposed to the ammonia, which you only add once at the start and then waited on it to drop to zero. During this time, you should occasionally test for nitrate too. The presence of nitrate means that nitrite is being processed, completing the nitrogen cycle. The nitrate level will also go off the chart but you will take care of that with a large water change later. It will seem like forever before the nitrite finally falls back to zero but eventually, almost overnight, it will drop and you can celebrate. You are almost there. Once the bacteria are able to process 4 or 5 ppm of ammonia back to zero ammonia and nitrite in about 10 to 12 hours. You are officially cycled.

At this point, your tank will probably look terrible with brown algae everywhere and probably cloudy water. As I mentioned, the nitrate reading will also be off the chart. Nitrates can only be removed with water changes. Do a large water change, 75 to 90 percent, turn the heat down to the level the fish you have decided on will need, and you are ready to add your fish. You can safely add your full fish load as your tank will have enough bacteria built up to handle any waste they can produce

Hope this helps, it took me only 11 days to fully cycle my tank

Answer 5

Sounds like new tank syndrome...

In established aquariums, just as in nature, toxic ammonia from fish waste is broken down by bacteria into nitrite, which is itself broken down by a different group of bacteria into nitrate. In a newly set up aquarium, those bacteria are not present in any quantity, and it takes time - about a 4 to 6 weeks under normal circumstances - for those bacteria to multiply to the point of being able to keep up with the waste output of the fish. “New Tank Syndrome” and “The Break-In Cycle” describe the period in which ammonia and then nitrite levels rise to dangerous quantities before being converted into relatively harmless nitrate.

I copied that from this website... It'll give you more info
http://www.bestfish.com/breakin.html

Answer 6

Do you mean 25 degrees Farhenheit? If so... wow.... they need to be at about 78 deg F.
You say you have a new tank... a lot of people have 'luck' dumping fish in a new tank and being fine, but really really you need to cycle your tank. Guppies and tetras need heat and air bubbles. I would buy something hardy first (oddly guppies are pretty hardy). Buy only a couple fish and a 'cleaner' like a pleco or cory (cory's are not as hardy as a pleco) let your tanks biologicals get going. It will take a few weeks to really let it cycle well.
Also... don't buy your fish from chain stores. Walmart, Petco, Petsmart...etc. Go to a local fish store, a store that only deals with fish.
You may have just had a sick batch of fish. You also don't mention the tank size. That could have been it.
I really hope this helped you out. Good Luck!!

Answer 7

you have got a 27 gallon tank on your hands with our standards

What you see is ammonia poisining, and the reason why it happened, is because you didn't finish the cycle of your tank
here is a site that explains cycling done in the proper way
http://www.firsttankguide.net/cycle.php

Also get an ammonia and nitrite test kit, as soon as these readings are at "0" you can start adding fish, but only about 6 at a time


Hope that helps



W

Answer 8

I would assume that these fish were diseased when you bought them, and I bet the pet shop has a 24-48 hour return policy that you could take advantage of. Also, there may be a setup time to allow the bacteria to acclimate to the proper levels (about 1 month in marine tanks). Have you considered thermal shock? When you put the fish in, did you keep them in their bags and put them in the tank to allow them to rise/fall to the tank temperature slowly?

Answer 9

did you put the tetras in all at the same time? you should put in a few then more weeks later also it might not be your fault the place i get my fish from get delivered to the shop on friday so i dont buy them untill about wednesday or the fish would of had three homes in a matter of days always check all the fish in the tank at the shop if some are acting strange dont buy any

Answer 10

ur tank has not been cycle properly mostly all of the products that sell cycling bateria are just a waste of money nex time properly cycle the tank be fore adding fish heres a site to help u http://www.firsttankguide.net/cycle.php