How to Clean a Fish Tank...

In this Instructable, I will show you how to clean an aquarium. The aquarium I will be using to demonstrate this process is a ten gallon tank with an under-gravel filter, stocked with five goldfish and a guppy. If your setup is different, don't worry. The process is pretty much the same no matter what type of tank you have (with the possible exception of a small goldfish bowl).

But first a little disclaimer. This is the way I learned how to clean a fish tank. It has worked for me without any problems. I have kept fish for years using this method, but based on the comments that are being left for this Instructable, some people don't seem to agree that this is the best way to clean a fish tank. Several readers are recommending to only remove a portion of the water while leaving the fish in the tank when you do a cleaning. This method works as well. Like I said, I have never had any problems cleaning a fish tank using the method described in this Instructable. Both work, so use whatever you feel more comfortable with when cleaning a fish tank.

Another thought is to consider what type of fish you are keeping in your aquarium. I keep goldfish which are very hardy fish, but they also are very dirty fish. Because of how fast they pollute a tank, I have found that the cleaning method of removing almost all of the water until it becomes hard to siphon that is described here keeps the water clearer and better smelling for a longer amount of time. If you have some more sensitive tropical fish (neon tetras for examle), I probably would go with the method of removing a portion of the water. Sensitive varieties of fish like this will succumb to even a small temperature change, so replacing all of the water while moving the fish to another holding tank probably wouldn't be the best idea in this case. This Instructable was written for cleaning fresh water aquariums. I have never kept salt water fish, so I am not sure of the cleaning method.

With those clarifications out of the way, here are your instructions for cleaning a fish tank...

Step 1 Set Up a Fish Hotel

Starting out, I'll assume you already have a fish tank that was well lived in, meaning the once crystal clear water has started to turn green and has a funky smell. It seems like fish really don't mind this at all, but the people that observe the aquarium do mind.

To solve this problem, you are going to have to remove the majority of the water from the fish tank. Before you do this though, it would be wise to put the fish somewhere else first. Otherwise you may end up with some dead fish.

Get a bowl of some sort that you don't plan on eating out of anytime soon. Clean it out very well, and then fill it up with tap water. Place it nearby the fish tank you are going to clean, and let it sit. You are letting the chlorine or whatever else they put in your tap water evaporate as well as letting the water reach room temperature. If you have a light or heater on your aquarium, turn them off now. You want the water in your aquarium and the bowl to be pretty close to the same temperature so you don't shock your fish any more than is necessary.

I let the water sit for about two hours and checked the temperature with a thermometer, and then I moved the fish, which is described in Step 2...

Comments

[tipsynoodle]

ok i have a question.....after i clean my fishtank, the next day it starts to smell again and the water is cloudy......i add dechlorinator and clean all decorations...my tank is a 30 gallon with various fish...(10 small ones).guppy, goldfish, mollys this happens everytime lately.....i empty the whole tank and start over each time. why is it smelling already?

[the fish guy]

Use the flag link above, this needs to be removed. On the other hand, a serious hobbyist would never follow this advice.

[cichlidstyle.com]

Never ever EVER use soap or chemicals to clean your tank. If you have an algae problem, move your tank where it isn't getting direct sunlight and/or add a fish (if you have room) that eats algae. Bristlenose catfish are small and love eating algae, saving you the hassle. Other than that, you can get a magnet cleaner that you can use every so often to keep the algae in check. More tips at cichlidstyle.com

[aattura]

Amen - no soap - if necessary a SMALL amount of Kosher (non-iodized) or aquarium salt to clean with will do the trick.

[cyna920]

I have used small amounts of Baking Soda (Arm & Hammer) for cleaning my tanks for years now; with no problems. Never use soap.

[devanden]

If you live in the city, you should add chlorine remover drops to neutralize the chlorine.

[king157]

are your fish dead yet? if not they will be soon because they need old water and no soap plus a form of stress reliever.

[blizz86]

this is only a suitable method for cleaning goldfish, with any other type of tropical fish this would kill/stun them in an instant

[ewansud]

You'll KILL your fish if the tanks is too clean! Use dechlorinator on new water. Don't wash anything with soap. The fish NEEDS the slim to survive. People prime a new tank for a reason! The bacteria breaks down the feces the fish produce into harmless substances otherwise the fish's gill, air bladder with be destroyed. As for algae your can reverse its growth by not turning on the light for a while. Trust me. I've made the same noob mistake before.

[codester]

I'm pretty sure that you're supposed to leave a little "dirty "water in the tank. The fish need some bacteria to survive. Good job though!

[aattura]

You are right about that.

[aattura]

YES - yes indeed -- if more than 2/3 of the tank water is changed, the fish run a VERY high risk of going into shock and dying. I never changed more than 1/2 of the tank's water at a time. And even though Goldfish are cold water fish, I was careful about HOW cold the new water was -- never too cold, never too warm.

[idyll23]

Please please PLEASE remove this until you have done ample research. This tutorial runs the risk of killing off many fish. Soap should never be used. Never leave your fish in a non-aerated small container unless you enjoy the thought of suffocation. Either pre-age your water in a large bucket or use a chemical additive. Leaving the fish out overnight is ridiculous.

[aattura]

"Either pre-age your water in a large bucket or use a chemical additive. Leaving the fish out overnight is ridiculous" TRUE!!! As for the bucket-- make sure it is stainless steel (test it with a magnet -- if the magnet sticks, the bucket is steel) -- NOT plastic-- many types of plastic will kill fish.

[DELETED_axol123]

(removed by author or community request)

[aattura]

Not really -- my GF lived very happy long lives in their fishie tanks. I have been a Goldfish Person for more than 20 years -- nothing fancy -- just good tanks, good outside filters and a good cleaning schedule. PS-- they DO try to talk to you!! <:-)

[aattura]

I had SEVEN Goldfish tanks at the same time -- 10 to 30 gallon tanks. I would partially clean each tank once a week (remove no more than 1/2 of the tank's water, clean off the insides of the glass). Then I would COMPLETELY clean each tank once a week (remove no more than 1/2 of the tank's water, remove caves and plants and wash plants on cold water and wash caves in hot water, remove outside filter, wash filter pads and filter in hot water and add a little TINY bit of salt water (kosher salt or aquarium salt) to the filter water. So...I was cleaning 2 tanks a day. I never kept gravel in the tank becuz it attracted goldfish poop and turned it into stinky ammonia. I never took more than 1/2 of the water out at any time because adding too much new water could kill the goldfish. I put borders of clear aquarium cement on the fish's caves when they were brand new, and let it cure -- so that when the caves fell over or were move in the glass tank, the borders were like rubber bumpers, and they did not break the tank. I never removed the goldfish. They stayed in the tank, and I used a sponge wand to clean the inside of the glass and the edges -- I wore long playtex (they didn't seem to hurt the fish) rubber gloves, and the siphon had a piece of nylon stocking rubber banded to the end so none of the fish's body parts would be hurt by the siphon. Since my goldfish lived to be 5, 6, and 7 yrs of age, I can say that my method of cleaning a fish tank worked pretty well too. I fed my fish twice a day-- I tried not to use vacation feeders because three of my fish got their mouths fused almost-closed by the scraping action of the hard feeder block - one eventually suffocated becuz I did not see this happen in time -- as for the 2 others, I literally had to reopen their mouths (cutting along the mouth line) with a sterilized swiss army knife so they would be able to breath and eat.

[aattura]

BTW-- NEVER pick up a fish tank when it has more than 1/4 of a tank of water in it -- or the sides may bow out and the aquarium caulking may be compromised and the tank may spring a leak. Water exerts a great deal of pressure on the sides of any fish tank.

[gonzalovalenzuela]

Very detailed, but change all the water isn't good, 50% its safer, because if you put all fresh water, the fish will be stressed and can die, and the change can be handle by the nitrifiers bacteria and the NO2 and NO3 levels will poison the fishes.

[Botfly]

I too have heard the same thing about removing too much water and too much cleaning. Not sure if it's a really bad thing but I only have an air pump and no filter. But I change about a 1/4 to 1/3 of the tank's water every three weeks or so. How often do you recommend this type of whole tank cleaning? My fish were doing great then I did a tank cleaning because it had been a really long time and I ended up killing most of the fish.

[aattura]

I did a 1/2 tank cleaning at the very most. I did it twice a week-- if you read my comment waaay abpve, you'll see that I never changed more than 1/2 of the water and I always added pre-treated water (add your drops of anti-chlorine etc, let it sit for a day before you change the tank) Doing a whole tank cleaning runs the very real risk of killing the fish

[madadam76]

THIS IS NOT "How to Clean a Fish Tank" And at the risk of being banned, but trying to keep some peoples fish alive......... Firstly, an aquarium is a delicate ecosystem, needing healthy water and bacteria to keep it and your fish alive. Using any sort of cleaning product is seriously bad! NEVER EVER USE ANY CLEANING PRODUCTS!!! This bacteria in your filter, water and under the gravel helps keep the toxin levels low, and ensures a safe and healthy tank. Chemicals kill this bacteria, causing the natural ' water cycle ' to have to begin again, most predominant is the ammonia cycle. Ammonia is poisonous to fish, burning their gills and thus causing them to have difficulty breathing, eventually the levels of ammonia will get too high and your fish will die from suffocation, amongst other things. This "spring cleaning" is a very bad idea. If you want to keep your fish healthy as well as the water you should do either weekly one quarter water changes, or fortnightly one third water changes, never replace all of the water. Always clean anything that you use in the filtration system, or any other hardware ( heaters, power heads ), rocks, plastic plants etc, that go in the tank with water from the tank. So, basically the only water your filter etc ever touches is from the tank. You don't need to take your fish out of the tank to do water changes, and so it is a much less stressful event. Mine actually seem to like the changes, swimming into the water being added back to the tank. *******************************ALWAYS************************************** Use a water ager, something that removes the chlorine from the water. I use Tri-start and it is very good, but any of the similar products are fine. please note: this is a recommended way of cleaning fish tanks, if you need information about how to look after an aquarium, choosing fish or any other questions go to an aquarium web site, you will get concise, relevant information, and not dangerous tips .

[Ohm]

Very well put, Me and my Dad have been keeping fish for years now and I just about fell over when I saw this.

[madadam76]

thanks, i would hope that the people that run this site would perhaps remove this "instructable", it is in no way helpful or safe. Ering on the side of cruelty to animals! Remember folks, treat your animals and fish as you yourself would want to be treated, if you were confined to one place to live out your existence. I can not tell you how truly upset this gross misinformation makes me.

[aattura]

My fish were my family members-- I guess I treated them even better than I treated myaself!!! They got the very best of care -- and no soap to clean their tank. I also do not believe they should be put into that bowl overnight -- that is a major stressor, and also -- they can easily jump out.

[woofboy111]

I wasn't expecting such forceful objections to the method that I use to clean my aquarium. I have been using this technique to clean my tank with no problems, so it seems to work for me. I have had feeder goldfish live for years and years using this tank cleaning method, so it works for me. I disagree about your animal cruelty statements though. While some would even say that keeping fish in a tank when they should be wild is cruel, if you do keep fish, wouldn't it be crueler to never clean the tank and let the fish die in the own filth... I guess all I have to say in the end is do what ever you think is best for your aquarium. I have never had any problems cleaning my tank this way, but if you want to only change a portion of the water, that works too!

[TOPEOLU]

I quite appreciate your courage to share these. You are doing a very good job. Everyone is entitled to his opinion, what works for one may not for the other. However, constructive criticisms is seldom necessary. "Woofboy111", keep the flag flying.

[Guppy8]

It isn't about having "freshwater" in the tank it is about having a good population of nitrifying bacteria tha can convert the ammonia from the fish waste into nitrite and then nitrate, so that the fish will be happy and healthy. Removing all of the water gets rid of the bacteria. With no bacteria, within a day, you will have an unstable ammount of ammonia and your fish will be stressed in addition to the stress of being moved around. While on the surface a full water change may sound better than a partial, it most certainly isn't.

[ultrauber]

agreed.

[madadam76]

Okay, if you think your right, then your right. I know your not, I know that your method is destructive and dangerous to the well being of everything that lives in your tank, fish, plants, bacteria. But sadly with freedom of speech, your entitled to your opinion, and I to mine, regardless of who may be right. People, if you want to learn about fish, read books, go to real aquarium stores and check out and even join a reputable aquarium site on the net.

[Guppy8]

madadam76 is right, you can think what you want, but that doesn't make your method a good one. Personally I think that not cleaning the tank at all would be better than they way that you do it, but that is just me. I always cycle my tanks and do partial frequent changes...is that the right way...well according to experienced fishkeeper, yes.

[Guppy8]

btw, keeping goldfish in a tank that small, regardless of the type, is not suitable. Even telescope eyes are too big for that tank. Just out of curiousity, how big do your comets grow?

[SamuraiGoose]

You should not post this kind of instructable if youren't an expert on the matter. Madamam and Amaya are right. You got to use siphon to remove dirt from gravel once a month or 3 weeks reduncing only 1/4 of water Soap of any kind must never be used (I recommend boil the decoration and then wash it in feash water) All Water must never be changed unless you are in serious desease problems. Also, real aquarist must use real plants, they preodce oxigen and consume dirt. nice fish by the way You should read a lot more about aquarism so you can post this kind of instructable.

[aattura]

"All Water must never be changed unless you are in serious desease problems.' AMEN to that!!! Also, real aquarist must use real plants, they preodce oxigen and consume dirt. True -- but they also got smelly in my tanks-- so I had to take em out and clean them once a week. I used ultra filtration but my goldfish were just champion poopers I guess. I ALWAYS used outside filters and put a thick screened "hamster-type" tank screen on the top of the tank (to alow for more air circulation), with careful coutouts on that top-of-the-tank screen, to accomodate the filter and made sure there were no gaps to allow the fish to jump out.

[shinobiAJC]

hey, iam currently looking at your advice on how to clean a fish tank. i have worked in an aquatics centre for about a year and have kept fish for 10yrs. i would never remove my fish from a tank while cleaning, this is due to the high stress levels which the fish will be prone to, and stress is the quickest and biggest killer of any fish. Second, if you insist on moving the fish, use water from the aquarium but do not feed them as increased stress levels reduce the fish's ability to digest food effectively, and could cause a bacterial infection in the gut, once again resulting in death.

[Czyne]

In addition to all of the previously mentioned points that removing all of the water is very stressful to the fish as the untreated tap water will kill off every bit of nitrifying bacteria thereby sending your aquarium into an ammonia cycle which, if it doesn't kill your fish altogether, will make them very distressed (they shouldn't become 'sluggish' after you clean their aquarium, how is sluggishness in any way something to be unconcerned about?) --- I'd also like to say that you SHOULD NOT tell someone who has to look up how to clean their aquarium to fill their entire aquarium with distilled water. Not only does it remove most of the trace elements/minerals from the water which your fish need to thrive, but there are no buffers present, rendering the pH EXTREMELY touchy. ALWAYS know what you're doing when messing with the parameters of your water to this extreme, you will need to add minerals and buffers that mimic the fish species natural habitat, and you wouldn't want to use distilled or RO water at all for fish that like very alkaline water such as lake tanganyika cichlids. You also shouldn't keep any kind of goldfish in a 10 gallon aquarium due to the size they get, as was previously stated. Sure, they may not visibly outgrow your tank, but their skeleton will continue to grow and cause deformities, making for a premature death. And guppies are tropical fish that like a temperature of 75-85 degrees F, which is above room temperature and too hot for goldfish, they should not be kept together. Plus leaving your fish in a cramped, unaerated bowl overnight in water with different parameters than what was in their tank is irresponsible. If you must remove your fish from their home for any reason, you should fill their holding container with water from the aquarium to eliminate shock, not from another source. If you're doing a complete overhaul because of disease I'd suggest a slow acclimation to the new water from a holding container filled with water from the aquarium- add some fresh water, remove some water, add more fresh water, repeat- over the course of about an hour (more or less depending on the sensitivity of your fish) so that they have ample time to adjust before placing them in the fresh source. There is just so much wrong with this 'How to' - I'm amazed it hasn't been removed considering how many poor techniques are being practiced here. Treating your fish this way is cruel, their mopey and sluggish behavior reflects that whether they bounce back from it or not.

[zstarski]

Many times if you add snails or some type of bottom feeding suckerfish you don't have to clean the tank at all

[halo99]

you got the same tank as me!

[cichlidstyle.com]

Although effective, this method puts a whole buttload of stress on your fish, which subsequently poisons the water apon their return (through the secretion of stress slime). A much easier and friendlier way is to remove 10-20% of the water in your tank every week with a gravel siphon hose into a bucket. Clean your filter media in the water that you have just taken out (so as not to kill the good bacteria). Reinstall your filter(s) and top the tank up with water. If you are refilling from the tap, make sure you ad a water ager and chlorine killer, otherwise the chlorine will kill your fish! Done! For more info on fishkeeping, whatever type of fish you have or want, look up cihlidstyle.com - people who live for fishkeeping :)

[Sgt.Waffles]

Over stocked and under filtered. Anyone who disagrees needs to reevaluate their dedication to the hobby. Have fun killing off all of your nitrifying bacteria when you rinse out your "filter cartridges".