Introduction: Condom Ecosphere

Picture of Condom Ecosphere

Create the circle of life... in a condom! This ecosphere, similar to ones developed by NASA, will last a reasonable amount of time if left in indirect sunlight during the day. Very fun and maintenance free. Fishtank and focal point of desk!


Condom Ecosphere Vid
Click play to watch. Thanks all, took a lot of work.

Step 1: Watch Video.

Picture of Watch Video.

Start off by opening and cleaning condom with water. The thinner the condom, the more easy to see through, but the weaker.

Step 2: Pour Gravel, Plants, and Snails

Picture of Pour Gravel, Plants, and Snails

Pour your gravel, your plants, and your snails into the condom wit water. Use a funnel or make one out of a bottle (as shown in video). Be gentle as this is when you are most likely to pop the condom.

Step 3: Add Fish

Picture of Add Fish

Add your fish. I like to use neon tetras because they are small and won't eat the adult snails.
Make sure to hold the lip of the condom, as it will want to lose grip as it fills with water.

Step 4: Tie Knot

Picture of Tie Knot

Now tie a knot in your condom, like always when finished!


Zrcalo (author)2016-01-17

You cannot keep fish in an ecosphere. period. You cannot keep a fish in this. period.

This is only a tutorial on how to inhumanely kill a fish. This will NOT work.

holymoses (author)2015-07-18


C O N G R A T U L A T I O N S!

What a realization, so why don´t you just delete this stupid idea!!?!?!

last_decoy (author)2008-07-01

hahah now when the fish dies from pure lack of oxygen you can flush them both down the toilet... i could suggest putting sea monkeys into the condom... but it seems most of us already do... honestly, i put potatos in theis things cause they have a better seal around them when they fly out of the potato cannon! im serious!

animal lover (author)last_decoy2013-07-21

thats sad. but it says that the plant produces oxygen. still wondering about the food though, does it eat the plant? hmmm...

flying pie (author)2010-05-16

i feel unconforble im goung to leave

Gage987 (author)2009-12-20

hang the condom with the top open and feed through it

555mst555 (author)2009-06-18

what about food?

mouthwashninja (author)2009-01-10

hahaha I'm studying to be a high school bio teacher and I think I just got an idea for a project. :P

blondie luvn ryan (author)2008-04-25

um well i think dat yah dat kewl but like idk kant u just go and get a taknk?

DeLorean4905 (author)2008-03-25

those are uhhh... those are some mighty swimmers you put in that rubber

w00ty32 (author)2008-03-24

hey i think if you use a magnum condom it wont break...... look at this test

austinblan (author)2008-03-12

why did you do this if you put a warning saying DO Not Attempt?

o0JohnnyReb0o (author)2008-02-27

Nice, and what do the fishes eat ?

Meraiah (author)2008-01-09

I thought your little video and creation is wonderfully smart...

GrinnDaddy (author)2007-11-17

This instructable has been rated as one of Grinn Blog's10 REALLY Wierd Instructables. Congrats hydrosliders!

deadly.jello (author)2007-07-24

dude! that is so hot!! wow! i would be worried about the fish a little......but i guess i could try it wit shrimp? i might try it though...looks cool

blingity (author)2007-07-11

isn't that kind of redundant/ironic?

hondagofast (author)blingity2007-07-14


A_squared (author)2007-07-10

Thats Awsome! I'll have 2 make 1

onemisterchristian (author)2007-07-05

Just to let you know unless you are performing water changes daily, in such a small volume of water, there is going to be a constant build up of nitrites, nitrates and ammonia. All three of which are either harmful or deadly to fishes systems. Also, the fish you have chosen, although small should not be kept in anything under five gallons. They're a schooling fish that is very active and needs more room. Sorry if I've discouraged you at all, just trying to keep you informed.

the plant converts nitrates and ammonia to oxygen.

A single plant can not be used as the sole means of filtration for biological waste. Especially because you also have to take the snails into account as waste-producers. Although the do good in cleaning algae and bacteria, the still must be considered into the bio-load when deciding on filtration options.

Tbh, biospheres work. Possibly he had the wrong plant. My dad's secretary had a biosphere in her office for a little more than a year. My greatest worry would be the chemicals in the latex.

zipykido (author)Mitten2007-07-05

Only bacteria have the ability to denitrify nitric acids (such as ammonia). Adding a small amount of pond water should put enough bacteria in the water to get you started. Though some aquatic plants have bacteria in their roots that can denitrify your water.

the plants don't adequately perform the function of reducing nitrogen/ammonia build up? also, the snails and bacteria help too. Mine lasted for a week and a half before I popped it trying to get some zoom shots. Everyone seemed healthy and are now in my main fishtank again. You might be right though... maybe i got really resilient fish luckily, and they were somehow able to overcome it, and may have died soon after... not sure.

SurferGeek (author)2007-07-07

I think fish of almost any size use more oxygen and produce more waste products than the small amount of plants you have could convert... by volume. What's the life span of a Neon? I have two of the original glass Ecospheres that are going on 10 years old.

mycroftxxx (author)2007-07-06

Points for creativity and amusement, but this really is only good for a week or so at most. Now, it is possible that your little econdom would have run longer than that, even indefinitely, but this would not be the normal experience of most people trying to follow your instructable. (I say this because I've read interviews with the ecosphere people who have talked about finding a "forgotten" sphere that had been in a lightless closet for 3-4 months and was healthy when removed, having found some non-photosynthetic metabolic pathways it could run on for a few months) Seriously, though, this is an art project, not a mesocosm. Other people have pointed almost all of it out: Lack of nitrifying bacteria, lack of sufficient plantlife for robustness, lack of sufficient water to buffer the environment, lack of a hardy apex predator, and unknown container properties. That being said, it is cool you managed to get this to work at all. If this has sparked your interest in mesocosm/closed aquatic ecosystems, that's very cool. I would suggest editing this instructable to include some sort of "DO NOT ATTEMPT" disclaimer at the top, as the stresses this particular ecosystem will put the living things comprising it under would constitute a form of animal cruelty.

Thelemic_Potter (author)2007-07-06

Guppies might work better, they are puddle dwellers and are far hardier. They also breed all the time, where as tetras are rather difficult to get to mate. Tap water is a real issue, the chlorine content is toxic and you need to let it sit out for at least 24 hours to make it safe. Better yet get distilled water, start up with the plants for a day or two, then add snails, then add fish. Not to mention the chlorine will break down the condom. I'm more concerned about the chemicals in the condom, lube, spermicide, latex...none of these are very good for life.

drummonkey92 (author)2007-07-06

if the fish eat the snails, wouldnt the snails need to breed realy fast to not become 'extinct'

You've never had a fishtank with snails before i take it? Like tribbles, they are born preggo and when you see one snail, soon there will be many. I've seen a tank go from one to two hundred in a week or so.

threecheersfornick (author)2007-07-05

How d'you feed the fish?

The fish should eat the baby snails as they are born, or the shrimp. Tetras can also get by from nibbling on plants/algae.

Hmmm... maybe that's why mine lived so long without food... :D

dchall8 (author)2007-07-06

I think that's a brilliant and wrong idea.

Fenwick (author)2007-07-05

"Create the circle of life... in a condom! " Anyone else sense the irony here?

Andrew546 (author)Fenwick2007-07-05

only a little ;)

joejoerowley (author)Fenwick2007-07-05

Yeah thats funny!

punkrunner204 (author)2007-07-05

Fenwick! your right.

ac1D (author)2007-07-05

How can i feed my fish after?

the fish should eat the shrimp and some types of fish might eat the plant depends on what type of plant it is through.

thematthatter (author)2007-07-05

are you using tap water! if you get 40-50 of these you might be able to grow your own lunch.

!Andrew_Modder! (author)2007-07-05

wouldnt the condom only be good for like a month or so??

Austinbwood (author)2007-07-05

Thats awesome. no lie. i might try this. nice instructable

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