fish cycle question.?

Question

what happens to the cycle process if the fish die? do i have to start again? or can i do a slight water change and continue with new fish? I will be cycling my 2.5gallon tank tomorrow with 2 or three neon tetra fish so i would like to know in advance what happens in the event they die..

Thanks guys. The size of the tank has really got me thinking about other forms of life i can keep in it. I already have java fern and moss in the tank which i bought earlier and if i were to decide to just keep shrimp in the tank instead would i have to cycle it?

Answer 1

No you do not have to start over again. Let the tank run. You really should not use fish to cycle a tank anyway. Get yourself a test kit. Allow your tank to run with no fish. Test your water and when the ammonia and nitrites are low below .5 your tank is ready to house fish. If you are using fish and they die, just remove them from the tank. Keep the tank running.

You can do a water change but really isn't needed unless you are planning to put more fish in.

There are three stages of the nitrogen cycle, each of which presents different challenges.
Initial stage: The cycle begins when fish are introduced to the aquarium. Their feces, urine, as well as any uneaten food, are quickly broken down into either ionized or unionized ammonia. The ionized form, Ammonium (NH4), is present if the pH is below 7, and is not toxic to fish. The unionized form, Ammonia (NH3), is is present if the pH is 7 or above, and is highly toxic to fish. Any amount of unionized Ammonia (NH3) is dangerous, however once the levels reach 2 ppm, the fish are in grave danger. Ammonia usually begins rising by the third day after introducing fish.
Second stage: During this stage Nitrosomonas bacteria oxidize the ammonia, thus eliminating it. However, the by-product of ammonia oxidation is nitrite, which is also highly toxic to fish. Nitrites levels as low as low as 1 mg/l can be lethal to some fish. Nitrite usually begins rising by the end of the first week after introducing fish.
Third stage: In the last stage of the cycle, Nitrobacter bacteria convert the nitrites into nitrates. Nitrates are not highly toxic to fish in low to moderate levels. Routine partial water changes will keep the nitrate levels within the safe range. Established tanks should be tested for nitrates every month to ensure that levels are not becoming extremely high.
Now that you know what is happening, what should you do? Simple steps such as testing and changing the water will help you manage the nitrogen cycle without losing your fish.
What To Do
The key for success is testing the water for ammonia and nitrites, and taking action quickly when problems occur. To aid in tracking the status of your aquarium write your results in a note book.
Test for ammonia: Begin testing on day three after adding the fish, and continue every day until the ammonia begins to drop. After it begins to fall, continue testing every other day until the ammonia reaches zero. Should ammonia reach the danger zone, take stepslike water changes to clear the problem. If at any time fish show signs of distress, such as rapid breathing (gilling), clamped fins, erratic swimming, or hanging at the surface for air, take immediate action to lower the ammonia level (Water changes). Test for nitrites: Begin testing one week after adding the fish. Continue testing every second or third day, until it reaches zero. If at any time fish show signs of distress, such as rapid breathing or hanging near the surface seemingly gasping for air, test for nitrite. If levels are elevated perform an immediate 25% water change and test daily until levels drop.
What Not To Do
Don't add more fish - wait until the cycle is completed.
Don't change the filter media - Or rinse it out
Don't overfeed the fish - when in doubt underfeed your fish. Remember that anything going into the tank will produce wastes one way or another.
Don't try to alter the pH - the beneficial bacteria can be affected by changes in pH. Unless there is a serious problem with the pH, leave it alone during the startup cycle process.

Answer 2

If you should lose fish duiring the cycle it will produce a weaker, less abundant cycle in the tank, but it will cycle none the less assuming you still have any fish at all in the tank. If you lose all of the fish you can replace the ammonia production from the fish with fish food and simply allow it to rot to produce the ammonia needed. In fact, I would suggest you not use fish at all to cycle the tank but instead just use ammonia or food or even a very small piece of raw fish or shrimp to produce the ammonia you need. You can increase the tank temperature to 82-84 and speed up the cycle process this way and not risk losing fish either.

Just grab an ammonia and nitrite test kit and feed the tank daily until you see very high ammonia, then stop feeding and watch for the ammonia to come back down. You'll see nitrites then and watch for them to drop as well. Once that happens you can give the tank and water change and add a reasonable fish load to the tank. This is actually easier and quicker than using fish.

MM

Answer 3

Ok here's the deal, I thumbed down Danielle for the following reason. It's NOT accurate that your cycle will keep going without fish. That I am sorry to say just is plain outright not true. If you put fish in there and they die, your cycle will continue ONLY for as long as thier is a fuel source for the bacteria to consume. A stoppage of fuel source will result in your colony, however far along it is established dying off. I have to say most of the other information she presented is true. You can do fishless, you can also do your cycle with fish, and if done properly, will not result in any extensive damage to them. Word of advice here, don't use those neon tetra's you mentioned. They are VERY sensative to shifts in water chemistry and too delicate to cope with the changes in it. Zebra danios, mollies, platties, guppies even would work. However, this is only a 2.5 gallon tank, thats VERY small. I am not sure what kind of long term fish you want to put in there, I am thinking you want neons long term. Use a zebra danio to get your cycle going. I know many people advocate fishless cycling and I hold nothing against that. But in so far as bacteria goes, if they do not have the fuel source they die, there is no disputing that because thats a fact. Consult with MM or Copperhead on this if you feel I am in error. Your cycle process will stop and if stopped long enough will result in you going back to day 1. Please don't use those neon's I am 99.9% certain they will not make it through the cycle.

Everything else mentioned by Danielle is actually pretty good. The bacteria in question is Nitrosomma and Nitrobaciter for Ammonia and Nitrite respectively. They oxidize down to each compound ultimately leaving you with nitrate, easy enough to handle with simple water changes. In an eco system that small however, your water changes are really almost down to a matter of cupfulls but you do need to give the nitrate build up some assitance it staying at non lethal levels.

JV

Answer 4

I always set up a tank with fish. I fill the tank up and leave it for 24 hours, merely for the temperature to stablise. Until you start adding fish the parametres of the water will not really change. Fill the tank up with COLD TAP WATER. Warm tap water can often be cloudy where it has sat in a tank warming for a little while. Allow for the heater in the tank to heat the water for you. Add the right amount of dechlorinator (often a blue liquid) for the amount of litres in your tank. Let the tank circulate for 24 hours at least. Once you have allowed your tank temperature to stabilize buy some hardy cheap fish. The reason for this is because the first 2-3 weeks your tank will go through a stage of peaking in certain pollutants. This is because your fish produce a waste through their poo and wee. Your filter cannot adaquately take this out until the bacteria that grows on the sponge has grown enough. This bacteria feeds on a waste product called nitite and turns it into nitrate. The nitrate is what you dilute out of the water during water changes. By starting with fish in your tank, you give the bacteria waste to feed on. Subsequently speeding it up, and doing it in a more natural way.

Answer 5

You seem to have peaked the interest of some decent fish hobbyists...and I'll admit I haven't read all of their responses, but I did want to add my two cents (sorry if they've repeated this).

Grats on the decision to step up in tank size! If I might offer a simple suggestion, save some fish's lives by performing a "Fishless Cycle". Instead of using ammonia created by fish waste, you use household ammonia. It gets your bacteria bed ready for a large payload (which allows you to FULLY stock your tank immediately after the cycle is completed) and in my experience, all of my tanks have cycled completely within 2 weeks.

I've included an article on the steps required to fishless cycle your tank, if you're interested. Good luck!

http://www.myfishtank.net/fishless-cycle/

Answer 6

I would start over again with a bigger tank, anything smaller than a five gallon just don't work out for long! Your fish will be much more happy with a larger tank! Good luck!