What kind of fish can I have in a tank with no equipment?

no fish can live in something so small, its not even 1 gallon. and goldfish will not be happy without a filter. they will be dead within a week in something that small. the smallest tank you want to go for is a 5 gallon and in that you can keep a single betta, but it will also need a filter and a heater. if you cant provide the right sized tank or equipment that the fish needs dont bother getting one

dead ones

sorry to tell you this but you can't keep anything in there, a goldfish need 30 gallons per fish to be healthy and happy so sorry but you can't keep any fish, but you could keep some aquatic plants in there or many some cherry shrimp. hope this helps

dont even attempt it

Joe and Ganal have some great answers. Sorry, you really shouldn't / can't keep a healthy happy fish in there. I would just like to add this site cause it has boatloads of info and some really great (fish) people there: aquariacentral.com Check out the freshwater newbie forum, up at the top of each of the forum's they have what's called a 'sticky.' These are very informative pages and worth taking the time to read. :) just a thought, try googling the 'walstad method,' if you try and put even some shrimp in there this setup might be good for that. Additionally, air stones are actually not real stones (like I thought at first too). I guess you could call them artificial stones of a sort, but there is a wide range of them and things they are made of, ceramic, wood, sand, glass, etc. Anyway, they have a bunch of tiny holes in them and a short 'stick' on one end, the stick is attached to an airhose (thin tube) and this is attached to an air pump. And that's how airstones work. :) The pump pushes air through the tiny holes and aerates the water. (Most air stones should be soaked for an hour before turning on for best performance. They also have to be replaced eventually as they get quite dirty, but they are fairly cheap.) Most the plants at petsmart in the aquatic section are not actually aquatic plants (though they did finally add a few more true aquatic plants recently.) Most of the plants they have in that section actually grow in more of a 'bog' environment - their roots and maybe even bottoms can be emersed in the water but the top needs to grow above the water, this might actually work for a 'vase tank.' Some of the ones to stay away from for tanks are: umbrella plant, any of the grasses they have (except hairgrass, that is aquatic), and ferns other than listed below, shoot my brain just went blank. Some of the true aquatic plants at petsmart are: java fern - sometimes called (only here) tropical fern - these are great for newbies, they don't have true roots so just tie them to a rock or decor or even leave them floating, they get their nutrients straight from the water and only need low light. Anubias - basically the same thing, except they can get some nutrients through their roots, but still do best tied to something rather than planted. Slow growing low light plant. Hairgrass, bacopa, telanthera, crypts (usually called green or red crypts - low light plant), ludwigia, microswords, wisteria, amazon sword, these are all safe aquatic plants (rather than the ones they just try to sell as aquatic). You can also try the bulb packages, they come in both separated packages and combined packages. The separated packages usually contain either dwarf lily or apogeton bulbs. They combined packages usually have both of those plus an onion bulb (not edible for us, wrong type of onion). Unfortunately, the bulbs don't always sprout so you have to remember where they are in the tank so you can take them out later if they don't sprout (or they'll rot and mess up your water parameters, in other words,, could kill the fish). Good luck!

No fish will be able to live in there. All fish will needs filter for their tanks and also larger tanks. You also have to cycle the tank before putting in the fish or else you can expect to wind up with dead fish. Goldfish is definitely not an option. They grow big and produce a lot of ammonia. The smallest tank you can have for 1 fancy gold fish (with double filteration) is a 30/40 gallon tank. If you put any type of gold fish in that jar you can expect them to live a very short life. Bettas also need filteration for their tanks and a minimum of 5 gallons (other's will say they don't need that much water which isn't true). They don't need an air pump but they do need a heater because they are tropical fish. If you don't have much space just buy a 5 gallon tank kit (they aren't expensive) and a heater for the 5 gallon tank (which also isn't that expensive) and get a betta. I'd say figure out what type of fish you want and make sure you do your research. Fish can be easy to take care of but there is more to it than providing a tank and feeding it food.

You cant keep anything in a 3litre JAR you just wasted your time creating a dream..

Please don't put any fish in there! No fish should have to be put inside a tiny little prison! Go get an actual tank if you want some fish.

I would put a pickle back in the jar and call it Fred. Actually a live plant and a shrimp would work, but not much else would live very long or be easy to keep.