How Many Fish Can Be In A 10 Gallon Tank?

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Determining how many fish can be in a 10 gallon tank requires consideration of a number of factors. The shape and dimensions of the tank will have an impact on the number of fish. In general, saltwater fish need more room than freshwater fish do. Within these broad categories the various species of fish often have characteristics which influence the population density of your aquarium. The level of tank maintenance you intend to perform can also impact the number of fish your aquarium can safely support. Regular partial water changes are key to the aquarium’s health and will increase the population size your tank can support.

General Guidelines

One general guideline that is commonly used is the one inch per gallon rule. This states that each gallon of water can support one inch of fish. The fish size refers to an adult fish. Caution must be taken when purchasing fish so you know their adult size. Fish sold in pet stores are often juveniles and will turn out much larger than purchased when they reach adulthood. You also need to consider the fact that some of your water has been displaced by substrate and tank decorations thereby reducing the amount of usable water.

A better guideline to use is to calculate the square inches of surface area of your tank. The water’s surface is where oxygen exchange occurs, so more surface area means more oxygen introduced for your fish. A standard 10 gallon tank is 20 by11 inches giving a surface area of 220 square inches. Using this number you then need to consider the type of fish you will keep. Using this rule you can go with 1 inch of adult fish per 12 square inches of surface area for slender freshwater fish such as tetras. More full bodied fish like cichlids should get closer to 20 square inches per inch of fish. Marine organisms require more space and should get 30 square inches of surface area per inch. In all cases a filter or air-stone should be in place to agitate the water’s surface which increases the tank’s oxygen exchange.

Suggestions For Stocking A 10 Gallon Aquarium

A 10 gallon tank is a nice size for a small community of freshwater tropical fish. I believe this aquarium size is too small to set up a successful marine environment. A great first step is to obtain some small catfish that will help maintain the tank’s cleanliness as well as being very entertaining to observe. Small Corydoras such as Pepper cats will thrive and you can add up to 3 to 4 of these. I always start a small aquarium with a few Corys.

This size aquarium affords you the luxury of keeping several species of fish or having a substantial school of a single type. Taking into consideration their size and compatibility you can go many different ways. You could go with 4 pairs of guppies of platties or a mix of both if you prefer livebearing fish. With these fish there is always the opportunity to find baby fish in your tank. Conversely you could go with a school of 12 to 16 neons or white-cloud mountain minnows.

If a varied community is more to your liking there are many ways to go. Tiger barbs are vary hardy fish that will do well in this size aquarium. They are fin nippers and should not be kept with guppies, but a combination of small tetras or platties with some Tiger barbs will work. I would suggest that 4 Tiger barbs with either 4 platties or 8 neons along with 2 Cory catfish make a nice community. You can substitute other small barbs like Rosy barbs or Cherry barbs but its best to go with a group of the same species of barbs.

Small cichlids like the Ram will go well in this size aquarium. With 2 catfish you could safely keep up to 8 to 10 of these beautiful fish in a 10 gallon tank. Using the above guidelines there are many different combinations of fish you can house in your aquarium. Your best results will come from keeping to these size guidelines and avoid overcrowding your tank. A link to an estimator tool is included below.

5 thoughts on “How Many Fish Can Be In A 10 Gallon Tank?

  1. I’m getting mixed info as to how many Platies can go into my 10 gal tank. One Petsmart store said 6 another store said 3. I currently have 3 , when I went to get more, I was pretty much assured by a the 2nd store that if I get a 4th it will surely die in a few days.

    • Hi Ronda,

      Just test, because the exact number of fish that your tank can accommodate will depend on many factors.

      Before you add more fish, make sure that these fish are healthy.

  2. Hi. For a 10 gallon tank you mentioned 4 pairs of hippies or platties but I was wondering if this includes the 4 starter Corys or if you should have them in there with the 4 pairs. Thanks

  3. I’m getting a pair of hybrid cichlids called the (RED PHOENIX KING CICHLID) they are hybrids the male grows up to a large 28 or 32 inches the female 20″ they are extremely extremely extremely extremely extremely aggressive/territorial/quarrelsome and predatory . I will be swelling the babies Toma pet store near you.

  4. The problem today is purists killing hybrid cichlids I do not tolerate this I like hybrid cichlids a lot and don’t worry there will be a hybrid cichlid revolution anyone killing hybrid cichlids will deal with protests and sites being taken over by us.

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