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Starting up a new 10 gallon tank requires some skill. How many fish can safely be added to a new small aquarium?


July 9, 2006 at 3:04 pm
(1) Tim says:

I heard that about one inch long fish per gallon is pretty good. Goldfish require a bit more space, though. Fish love their space!

December 30, 2006 at 11:27 am
(2) Savanna says:

Never have 1 inch per gallon. Would you put a 10 inch parrot cichlid in a 10 gallon tank? If you want to be fair then NO! 1 inch to every 4 gallons is a more realisic estimate. We can’t stop you from overcrowding your aquarium though. just try to think of yourself as the fish.

February 21, 2007 at 9:17 pm
(3) Casey says:

An inch of fish per gallon is an okay guideline for freshwater fish, especially if you have a good filter with a bio wheel. However, there are more humane ways to cycle your tank. If you use a live fish to cycle the tank, it will be exposed to high levels of ammonia and nitrite, which is toxic to fish. Google “fishless cycling.” It’s easy, and you won’t have to harm the fish!

April 10, 2007 at 3:25 pm
(4) mia says:

i have a koi fish, and 3 goldfish, all of which are just little guys my koi is probably 2” and my goldfish are all under 1”… i have them all in a fish b0owl, like the round one. im not totally sure if that is okay.
However, i do have a 10 gallon tank that i am going to use for some other fish, maybe tropical, like angels or somthing. im not sure. i dont really know much about fish and their living requierments, so if this gave anyone a red flag, or if you guys have any suggestions, pleasee comment back!!!

July 26, 2007 at 4:03 pm
(5) sammajamma says:

i think its 1 inch per gallon, but if you want your fish to have a little space then i would do 1 inches per 3 gallons

August 29, 2007 at 3:16 pm
(6) kirsteen says:

ummm well i’ve never had more than one fish i once put 3in a 10 gallon and they died. so dont over crowd it so i would say what 2-3 fish

July 16, 2008 at 12:30 am
(7) unknwn says:

i got a 10 gal. had 16 in there (1 died today) so 15 now. not too crowded. wide range. id cap it at 20 TOPS//

July 26, 2008 at 9:20 pm
(8) Fishface says:

You guys are spouting some pretty ignorant information concerning fish and tank setups.. Angelfish in a 10gal tank? Uh, sorry.. Not even one Angel should be in a 10gal tank. You people realize that fish don’t stop growing in order to accomdate their living conditions.. They are externally stunted, yet their internal organs continue to grow until they die a painful death.. READ.

February 20, 2009 at 2:06 pm
(9) Fish lover says:

I am thinking about getting a 10 gallon tank and some swordtails or some guppies or mollies how many swordtails,gupies, or mollies can fit in the 10 gallon tank. i need to know this soon so i can get it and have fun with my fish

February 26, 2009 at 2:57 pm
(10) dogyluver says:

a 10 gallon tank is really only good as a breeding, hospital, or quarintine tank. And 1 inch per fish is not realistic at all, it’s just plain cruel the fish can’t even swim in that space.

March 1, 2009 at 1:21 am
(11) Meme says:

Coming from a pet care specialist, the rule is one inch of adult size fish per gallon. So, if a fish adult size is 2″, then that’s 2 gallons needed. Angelfish need a minimum of 20 gallons. The best freshwater fish for a 10 gallon aquarium are tropical fish that grow no more than 3″. There is absolutely nothing wrong with a ten gallon tank. The main disadvantage is that you’re very limited in space, so choose wisely and ask for assistance at your local pet store!

March 1, 2009 at 1:59 am
(12) Meme says:

Also, it’s best to start out with a small tank. Think of it as a practice tank, and once you get the hang of it you can go for an upgrade. Ten gallons are perfect for rooms with minimum surface area. Although the known rule I’ve been taught was “one inch of fish per gallon”, you have to remember that gravel, artificial plants and ornaments are taking up surface are as well! Cycling and tank maintenance is very important for beneficial bacteria to thrive. I recommend starting with a basic school of fish such as barbs and tetras that grow no more than an inch and probably no more than 5. Be careful not to overpopulate which can lead to various fungus and bacteria; not to mention destroying your tank’s delicate ecosystem!

May 6, 2009 at 2:47 pm
(13) Cam says:

The rule of 1″ per gallon means this:
10 1″ fish would work bioload-wise in a 10 gallon tank. A 5″ fish does not equal 5 1″ fish though. This is because weight is more important than length. A 5″ fish would be closer to 30″ of fish when you look at what kind of bioload the fish has. Under no circumstance should any fish be kept in a bowl. Fish really need a filter. Even bettas. They can breathe air but very rarely does anyone ever have enough time to change the water regularly enough to really make sure that the water quality is good enough.

June 9, 2009 at 5:40 pm
(14) aleman says:

i keep 10 zebra dainos, 7 neon tetras,3 ottiniculs,1 beta in a 10 gal so i gues it would be ok if they ar small fish but dont keep a angle fish unless in in a 50 gal

September 12, 2009 at 2:20 am
(15) Sebastian says:

I currently have 2 Zebra Danio, 6 Scissor Tails, 2 Guppies and a scavenger catfish in my 10 gallon. They’re pretty small fish, so it’s fine. Never keep Angelfish in an aquarium smaller than 50 gallons, they get big and they need their space.

October 27, 2009 at 10:33 am
(16) klaubo says:

Cam you are absolutely right one five inch fish does not equal 5 one inch fish, the bio-load is much more. I must say a ten gallon tank is just fine, so long as the filters (both mechanical and biological) can keep up with the tank population rule of thumb- Filter should move twice the amount of water of the tank every hour meaning 10 gal tank filter flow 20 GPH (most are more than that always better safe)

October 27, 2009 at 10:41 am
(17) klaubo says:

Also a larger tank is best to start out with, while they are more expensive the benefits are twofold. 1 mistakes are more forgiving in a larger tank, one fish dying in a 55 gallon tank wont cause an ammonia spike high enough to kill off the rest of the tank however the same fish dying in a ten gallon tank with less water volume and smaller filter will be a toxic nightmare. 2 When you get the confidence boost to add more, you can just simply do as such, no need to run out and purchase another complete set up or waiting for the nitrogen cycle (to an extent) just food for thought.

December 31, 2009 at 12:35 am
(18) Draketeeth says:

Congratz on your new tank! For a tank of that size you’ll want to look into fish that get no bigger than 2-3 inches at most. Anything larger than that would probably be too much for your tank to hold.

If you’ve never kept fish before some good starters are neon tetras, zebra danios or leopard danios, barbs or bettas.

With bettas you would want to do a single male betta with another community species, a single female with another community species, or you can do a community tank of females. With a community of only female bettas you’ll want 3-4 for your tank size and lots of hiding places. A male cannot stand to be with another of his species, but the ladies endure each others company and establish a pecking order. This is why hiding places are important. When one of the gals has been picked on enough, she has a place to hide and recover. Male bettas should not be kept with male guppies, as the guppies fancy fins look much like a rival male in the bettas eyes.

Other popular beginning species are mollies and guppies. The ratio to keep them in is 1 male to every 3 females. If you do any less females, the male can harass the gals literally to death in his attempts to breed with them. The more females in the tank, the more bodies to spread his attention across. You can attempt to do a single gender tank with either of these species, but as a warning I’ve heard that they can gender swap when populations are unbalanced. Another warning would be, they have lots of babies. I did guppies for my fish when first starting and was quickly on over load. My 1 male to three females quickly went to over 25 fish in less than three months. If you do a livebearer, know what you’re going to do with the fry. Mollies and guppies are known to eat their fry, so you can choose to let the survival of the fittest take care of the fry (which has still left my tank on overload), or set up a secondary nursery tank for the young. Another livebearer option would be a Lesser Killifish. They’re a small fish maxing out at an inch or so who are constantly pregnant. The females drop 2-3 fry every day and have different stages of developing young in her belly. These killifish are not known to eat their young, but due to their small size, raising the fry is a special trick as they cannot take the crushed flake food instantly like guppy and molly fry can.

Another interesting starter fish is a kuhli loach. These guys are eel-like fish with funny whiskery faces. They are omnivorous and enjoy both algae pelets and meat based fish foods. They probably would also love brine shrimp and bloodworms given the chance. They are nocturnal, but do adjust to a daytime feeding schedule. If you want to see your loach, keep it in a group of 3 or more. The more there are, the better they do. A single loach will hide. These guys can do well in a peaceful community tank and are not known to pick on other fish. They can get up to 4 inches long. A tank with loaches is typically a snail free tank, as the loaches find snails to be a slow moving tasty snack.

If you are up for a challenge and want to try your hand at breeding, Scarlet Badis (dario dario), or Clown Killifish might be up your ally. The Clow Killifish max out at 1.5 inches in size and dwell in the upper to middle areas of the tank. They are peaceful and short lived, their lifespan end at a little over a year old. They do breed in captivity under the right conditions and take flake foods. However this species is somewhat fragile and prone to dying if water parameters tip out of their favor. Stress from shiping may also play a factor in their early demise. They do better in an established tank over a new one. Availibity of this species is in question. I have been looking into them and finding them is difficult. Possibly they are more easily found at certain times of the year?

The Scarlet Badis seems to be the same as far as finding them available. I have been looking and have been somewhat unsuccessful in finding them in my area. The Badis, or Dario as it is also known, is another small species an inch in length. These guys like to hang out on the bottom of the tank and establish territories which they defend from other fish. When keeping these hiding places are a plus as they will hang out in their holes and establish the territory around it. For a 10 gallon 3 breeding pairs is possible, though I recommend starting with a single pair and seeing how well you like keeping them before expanding. Males are more colorful than females, and more readily found since more males are imported than females. It may take a little time to find a pair depending on where you get them. The Scarlet Badis likes live and frozen foods. They think flake foods are a joke. They are also slow eaters and will not chase after a meal drifting by them in the water. Feeding time takes 5-10 minutes depending on how many you have and how fast they decide to chew. They do not like strong water currents.

For an algae eater (when you need one), the common pleco is not the best option. A pleco easily outgrown small tanks in a hurry. Instead I recommend an Otocinclus. They are small algae eaters which seem to have an obsessive complusive tendency to erraticate algae. Efficent little workers, they do most of their work by night and appear lazy by day. Diet can be supplemented with algae waffers. Any halfway decent pet store knows what an Oto is, a bad pet store will confuse it with a chinese algae eater. Know your fish.

Whatever you pick to put in your tank, remember to introduce it slowly. Too many fish too fast can send the water out of balance and kill or harm your new pet. It’s okay to buy a fish, wait a week, buy another fish. They don’t all have to be put in at once.

Best of luck!

January 1, 2010 at 4:47 pm
(19) Betta 4 Life says:

make sure you know what you are doing, i have a friend who overlodded his tank and it does not look pretty! Ask the people at the pet store what is the recommended amount of fish in that ten gallon of yours and happy fishing and new years.

September 2, 2010 at 2:58 pm
(20) Earl says:

I think that you will find the “one inch rule” to be great for a ten gallon tank but only when applied to small fish. Think about it. It works well with small tetras and such but try lining up five or six neon tetras next to a full grown Angelfish or fifteen neon tetras next to a full grown pleco and it is easy to see why the tetras will do fine in a ten gallon but the other fish won’t. Over the years, I have had success with the one one inch rule and guppies, female bettas, glowlight tetras, lemon tetras, serpae tetras, black neon tetras, swordtails, corydoras, and otociuclus in my 20g. I also have a bristlenose pleco in there and it seems to do well. I got a bristlenose because they do not get big and I wanted a pleco. Do not get a common pleco as they will grow to over a foot. There are plenty of smaller ones to choose from. Another is the candy stripe .

Also, if you want to cheat a bit, that is fine despite what people on here may say. I have had about 26 inches of SMALL fish in my tank, which was never a problem for several reasons. First, I am willing to clean it more often to keep up with the extra waste. I also have a large air stone and a waterfall filter to maintain good air circulation. It helps that some of the fish were female bettas that breathe air from the surface rather than the water. Just be willing to accept the extra hardware and maintenance and don’t be clearing the limit by leaps and bounds and you will be fine.

September 2, 2010 at 3:04 pm
(21) Earl says:

Mia, if you still read this, your fish bowl is ridiculous. Goldfish get huge and even one goldfish in a small bowl is too much. Maybe one or two goldfish in a ten gallon. Maybe. Find someone with an outdoor pond and donate the fish to them, especially the koi, which will grow to well over a foot. I promise they will be grateful.

November 30, 2010 at 9:45 am
(22) yooo says:

i have a 150 gallon tank with 2 catfisk that are 11ins long nd a 2ft clown knife fish wat should i give away m catfish or get a big tank because my fish fight over one coner of the tank nd ma clown knife cost me 5$ wen i got it at 3inches nd now i looked it up and the want around 275$ for him and i dont want him 2 die plz help

December 2, 2010 at 6:55 pm
(23) jals says:

I have 7 danios (longfin, golden, glo), 3 cory cats, 2 ottos (going to get 3 more, an amazon sword, and a flying fox in my 10 gal!

April 2, 2011 at 5:06 pm
(24) haley says:

I have a 10gal tank and I made the highly unfortunate mistake of not becoming knowledgeable about the nitrogen cycle beforehand and now I have 2 dwarf guaramis, 2 zebra danios, 4 guppies, an African dwarf frog, and 1 ghost shrimp. my tank is cycling now, so how do I keep all my fish and frog and shrimp alive throuh the cycle? I started with 5 danios 3 already died :(

September 27, 2011 at 12:34 am
(25) Malissa Williams says:

i have 1 male betta in a 5 gallon tank. ive just bought a 10 gallon tank and plan to move him. So i should cycle the 10 gallon first? can i add two cory cat fish? If yes, when can i add them? i hope my betta will not attack them, hes very spoiled.

February 21, 2012 at 2:59 pm
(26) Acroneeser says:
June 20, 2012 at 7:12 pm
(27) troublegoat says:

i have two 1 inch big crawdads in my 10 gallon tank with a small goldfish too and i had 3 but 1 of them killed him.its hard to house them because each morning i have to split the food into each territory for the crawdads but the fish eats whats left.hardy,feisty and mean little pets.good to care for though.

August 5, 2012 at 11:03 am
(28) Arman says:

Kois need ponds! And goldfish need at least a twenty gallon tank!!!!!! And one inch of fish per gallon is good as long as that fish is kept in the right size tank …. U couldn’t put a 10 inch parrot cichlid in a ten gallon cuz parrot cichlids need at least a fifty gallon tank but u could put ten guppies in a ten gallon tank! Guppies normally grow to one inch at the most

August 21, 2012 at 7:43 pm
(29) sexy beast says:

guys thanks for the tips im wayyyy happy about my 10 gallon tank!!!

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December 8, 2013 at 11:06 pm
(31) Bobby says:

i have 2 bala sharks , 3 mollys and 2 platties and one plecostomus in my 10g tank is that to much? or will they be fine i have had them in for about 2 week they been fine i just want someone elses opinion im new with fish.

February 27, 2014 at 5:23 pm
(32) Leila says:

Bobby: Yes, that is far too much. Bala sharks and plecos get way too big for a 10 gallon. On top of that, balas tend to be nervous, active swimmers, and sensitive to water problems. The only thing that tank can support are those mollies and platties. No more. Get the bala sharks and the pleco out of that tank or get a 75 gallon tank at minimum.

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