Now, you would have heard about what fish is compatible with what other fish for a particular eco system. However, lot of beginners are still looking for one of their basic question. “How many fish can I accommodate in a small fish tank, say 10 gallons (~ 37 liters)”? Why is this question important for a beginner getting into the fish hobby, or for anyone for that matter?

To start with, the primary response to that question should be the well-being of the fish. However, most of the time this is required to make sure the new pet owner doesn’t get stressed out since their fish is suddenly not doing well in their new big 10 gallon tank. Stocking takes such a big learning towards a successful fish keeping. Luckily, unlike getting the water parameters correct, this particular query can be addressed just be researching. That’s exactly what we are trying to answer here as well. Read on

How many fishes in my new 10 gal tank?

How big of a tank should I get? Now, that’s an entirely different topic. We will take that up in another article. Since you got your 10 gal tank, it is assumed you already read that article and understood why 10 gal is better than those bowls or teeny tiny tanks. Or, you just got lucky and randomly chose the 10 gal. Either way, now to interesting things. What fish to add? How many fish? Could I add all the fish at once? What should I do before adding the fish? As with anything, questions, questions and more questions. Well. That’s what makes a good fish keeper better. Or for that matter, makes everyone better. Question everything and learn more each day. Learning doesn’t stop at all.

Before you can add fish, there are some things you should consider which would have a direct impact on how many or what kind of fish you can have. These could be your expectations or what you are wanting to do. Let’s look at some basic things you need to look at before you actually add fish.

• Temperature
• Cycling
• Filtration
• Water Parameters
• Fresh water or Salt water

Since the main objective of this article is to discuss how many fish, we can skip past these. If you do want to understand the above topics, they are covered in a separate articles. Let’s assume you got these covered. I will add some assumptions for fish options but those are just assumptions.

Could I add gold fish to my 10 gallon?

Short answer. No. Long answer. Well. Hold on to your breadth and let’s get this started.

You see that tiny little gold fish in your fish store. Doesn’t it look beautiful? With its big round belly, beautiful flowing fins, variety of colors, bulging eyes. It evokes quite an interest. Doesn’t it? Some varieties of gold fish would also be sold as starter fish or feeder fish and they cost very low that you actually want to take the plunge. Well. I hate to break it to you. Don’t do it.

Those tiny little cuties has the potential to grow more than 1 ft.; most cases, more than that. By buying them you are making them grow in an environment that is not suited for them at all. Gold fish are also messy eaters and create a lot of waste. With such a small tank, it would be difficult for your good bacteria that live in your filtration to keep up with maintaining the parameters right. Short term, you’d see your gold fish getting sick or your water getting really dirty. You would spend a lot more time maintaining the tank with more frequent water changes. You would soon be cursing yourself with so much work you’d have to do or live with dirty messy water.

Long term, your fish would have a shunted growth. This means, the fish’s internal organs would try to grow at normal rate while the external body cannot due to the small tank. It would be extremely painful for the fish.

So, back to the question. How many gold fish can I add to my 10 gal tank? Preferably none since gold fish do not belong there. Unless you keep a small fish temporarily there before moving it to a bigger tank, it is not ok for a gold fish to be in 10 gallons at all. Even if it is temporary, water changes should be done daily, with good filtration and less feeding.

Ohhhhkkkkk. So, what do I do? I got this tank already. I really wanted a gold fish. Now you are ruling that out, what else could I get? Well. That opens up plenty of options. Let’s see what options we got. Shall we?

Before we get into what fish, let’s figure out how many fish. By now, if you are already doing your research, you’d have come across this wise-saying “1 inch per gallon of water”. Some sage or a wise-person introduced this to the fish community. Now, as with other things that is being said on the internet, including this article, you need to understand it fully before jumping onto conclusions. It is a guideline; it is a framework; however, not to be followed blindly.

There are different theories around this rule. 1 version states that you can have 1 inch of fish per gallon of water. This means, you can have up to 10 fish that are of 1 inch size. Or 5 fishes that are 2 inches in size. Well? Does that include the tail as well? There you go. Another question. Way to go mate. Happy for you. Now you are really learning. As I said before, question everything you read or listen.

Another version is that you should measure the cubic inch and not just length of the fish. This makes a pretty close to reality. How does this work?

For these calculations, use the max length the fish would get; not the length they are when you buy unless you are planning to rehome them or reintroduce them elsewhere soon.

Fish not just have length. Right? It has a shape in terms of length, width and breadth; 3 dimensions. So, if you take a neon tetra fish:

Length – 1.5”

Breadth – 0.5 “

Width – 0.5 “

If you multiply these data, it gives you (1.5 * .5 * .5) = .375 per gallon. Meaning close to 3 fish per gallon. About 30 fish for the 10 gallon tank. That would mean cramming lot of neons inside the 10 gallon. However, if you apply the 1 inch per gallon rule, that brings out 10 fish in the tank which makes it a better stocking option.

If you take a molly, then the lax length some mollies can reach are about 4 to 5 inches. It might also get ½ inch in thickness and another ½ inch in wide. That makes it (5 * .5 * .5) = 1.25 per gallon. This would mean 8 mollies for a 10 gallon tank at the max.

Following 1 inch per rule would have you try and manage a 10 inch Oscar in a 10 gallon tank. As you can see with this cubic inch rule, it can be calculated that the Oscar would need approx. 60 gallons per fish considering they would get about 3 inches in height and 2 inches wide.

From what we have seen, the inch per gallon works well for smaller fish while it doesn’t exactly apply well for bigger fishes. One should use their best judgement. May be, whichever guideline gives you less number, use that.

Now, let’s try to list some fishes that can fit into a 10 gallon.

Schooling fish (school of 6):

• Neon tetras
• Black skirt tetras
• Black neon tetras
• Cardinal tetras
• Ember tetras
• Rasboras (harlequin or emerald)
• Red-eye tetras
• Bleeding heart tetras
• Dwarf cory cat fish
• Honey gourami (1 or 2 max)
• Betta fish (1 male only)
• Shrimp if you are into it
• Snails if you are into it (some snails have heavy bio loads)
• Guppies ( max of 6)
• Platies (max 6)
• Endlers (max of 6)

If you are looking for something to stand out, look into species only tanks. When I say species only, it is best to keep just that specific species in the tank. Due to small tank size, it would be better not to mix with other species.

Some specialty fish that might be suited for a 10 gal tank are:

• African butterfly fish. With 10 gallon to play with, it is best to have just 1 of this fish in the tank. They are excellent jumpers and so a lid is essential.
• Cichlids. The only cichlid that would be suitable for a 10 gal is the Shell-dwellers. Very interesting fish and one would have lot of fun with this fish. They get only to about 2” in size

If you are looking for nature’s way of algae control using live animals, apart from Ottos, no other algae eater would fit this tank. Ottos are your best bet in fish. Nerite snails are good along with amano shrimps.

Ideas for a 10 gallon tank

You can mix and match to get the best out of a 10 gallon. If you prefer to have a betta as a center piece, you can add some cories (6 of them). Or you can add some snails or shrimp with the betta.

You can add a school of tetras.

What not to add in a 10 gallon

We’ve seen about how many fish we can add in a 10 gallon tank? On the flip side, we can also see what fish cannot be in a 10 gallon. As already discussed, gold fish is a big NO for such a small tank. Plecos are not suitable as well since they can grow up to 12” or more. Zebra danios are small fish but not really good for a 10 gallon since they are pretty active and fast swimmers. They need a much larger footprint and hence they should be avoided as well. Mollies and swords get bigger as well and hence not really suitable for a 10 gallon.

Those angel fish babies would look super cute at the fish store but they get very large and need tall tanks to have a happy life. They don’t belong in a 10 gallon tank either.

Summary

A fish tank brings peace and tranquility into your home (or your work place or wherever you choose to have one). It helps you relieve stress and focus more. By carefully choosing the best conditions for your fish, not only you are giving them a good life but also creates a stress free environment for you as well. Do your research, apply your best judgement, ask questions whenever you feel like and do the right thing. All the best and enjoy your little wet pets.