Stocking Aquarium on Different Levels

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There’s no denying that setting up a self-sustainable (or as close as possible) fish tank requires plenty of preparation, work, and brainstorming. The situation is even more complex when discussing community tanks with multiple fish species inhabiting the same environment.

The latter makes for a much more delicate situation for several reasons. One of them is the different fish species’ need for certain parameters and space. Not all fish are territorial, but most are to different degrees. So, you don’t want multiple fish species overcrowding one area while other areas are left uninhabitable.

This is precisely what we’ll be discussing today: stocking ideas for community tanks. In short, we’ll go over the best top, mid, and bottom dweller fish species to consider for your community tank. So, let’s jump right into it!

Top-Dwelling Fish

Top dwellers are generally active and energetic fish that provide your tank with a lot of personalities. It’s always fun to see the fish popping at the water’s surface constantly in search for food, some swift breaths of air, or simply when playing. Top dwellers are also more prone to jumping out of the tank, so you might also want to keep that in mind.

Some great choices for the top area include:

Silver Hatchetfish

This is a small, hatchet-like fish that looks exactly as its name suggests. The body is short, no longer than 1.25 inches, and the thorax is wide, similar to a pelican’s underjaw pouch. All hatchetfish are metallic silver in coloring, allowing them to sparkle in bright lights. While their diet is theoretically omnivorous, they prefer live foods over anything else. 

The ideal temperature is in the 60-82 °F range with a pH of 5.0-7.5. You need at least 20 gallons for this one, given that hatchetfish like to live in larger groups.

One thing to note about this species is that it is extremely active and jumpy in nature. Hatchetfish are known sometimes to jump several feet in the air, allowing them to escape their tank quite easily. So, you need to secure the tank with a lid to prevent that.

Also, I recommend keeping hatchetfish in a species-only environment, given that they don’t do well in community tanks. These are slow eaters that can be easily outcompeted and stressed out by faster and more aggressive eaters and swimmers. You can pair them with bottom dwellers just fine, though, considering that the hatchetfish will rarely leave the water’s surface.


You may know this one as the wrestling halfbeak. If you haven’t heard of the species at all, I don’t blame you; these are more exotic specimens than your regular guppy or pleco fish. Halfbeaks are awkward in appearance as they have very slim and aquadynamic bodies with a very long snout. They have tiny black eyes, a silvery body, and small orange dorsal and anal fins.

The fins are located near the tail, which means that the rest of the fish’s body is smooth, like a bullet. These are also adept jumpers, so a tank lid is absolutely necessary for them.

Aim for temperatures around 75-82 °F and a pH of 6.5-8.0. The water should be either brackish or fresh, depending on what other fish species you plan on adding to the aquarium; the halfbeak can handle both types.

Depending on the variety, your halfbeak can measure between 2.8 and 7 inches and requires open swimming spaces. These fish are particularly prone to beak injuries due to their long and sensitive snouts, so don’t use excessive water decorations near the surface. Also, expect halfbeaks to fight between each other constantly. I mean, they have to earn the ‘wrestling’ part of their name somehow, right?

Invest in at least 30 gallons of space for small species, especially for a community tank.

Boesman’s Rainbowfish

This is truly a gorgeous fish thanks to its compact body with very small and narrow fins and a rainbow-like color gradient. The typical Boesman’s rainbowfish will grow up to 5 inches in good conditions and adapt to a variety of water parameters. Aim for temperatures around 81-86 °F and a pH of 7.0 and 8.0. These fish love warmer waters, so you need to choose their partners with this in mind.

I recommend at least 30 gallons for 4-5 fish, although you can always go a bit bigger. These are very active fish in need of constant movement and exploration. Keeping them crammed or overcrowded in small spaces will stress them out quickly.

You should choose their tankmates carefully, given that these are fast swimmers that can stress out other companions.

Boesman’s rainbowfish are not pure top-dwellers, as they also patrol the tank’s middle area, so keep this factor in mind as well.

You can also opt for top-to-middle dwellers, some of which include neon rainbowfish, swordtails, pencilfish, guppies, etc. Make sure that all fish species are compatible in terms of size, temperament, feeding behavior, water parameter requirements, etc.

Middle-Dwelling Fish

Mid-dwellers are usually versatile, as there’s no such thing as a pure mid-dweller. These fish will often swim throughout the entire tank, patrolling the entire environment from substrate to the surface. That being said, they are most often visible in the middle area, typically in a shoal, minding their business.

Here are some good options to consider:

Tiger Barbs

This 3-inch fish ranks among the most popular mid-dwellers in the world. This is both due to their temperament and colorful presence, designed to bring a lot of magic and life to the environment.

Tiger barbs are usually pink with black vertical stripes, making them easily recognizable and quite lovable. These fish are omnivorous, which is another way of saying they’re not picky eaters. They are, however, picky in terms of their tankmates. Tiger barbs aren’t violent, but they are known for their bully-like mentality.

You should never house tiger barbs with long-finned slow swimmers, as these will trigger the barb’s bullying instincts.

You need approximately 20 gallons for a school of at least 6 fish (which is the optimal number of barbs) and temperatures around 68-79 °F. Since they’re very active, tiger barbs require more vast swimming areas with little interference in terms of plants, rocks, or any other decorations.

Discus Fish

The discus fish is the undeniable king of the middle area. This cichlid is absolutely gorgeous with its round and colorful body. Depending on the breed, most discus fish can reach between 5 and 8 inches and showcase an outstanding variety of colors and patterns. These fish come in colors like orange, brown, blue, turquoise, red, silver, spotted, randomized, or striped patterns.

They are even more impressive and impactful when kept in groups which is their preferred lifestyle anyway. I recommend a group of at least 6-8 individuals, for which you require at least 55 gallons of space.

Aim for temperatures of 82-88 °F and a pH of 4.0-7.6, which only showcase the fish’s adaptability and resilience. The tank layout should balance open areas and hiding places, especially rocks, live plants, and driftwood. These elements make the fish feel safer, calmer, and bolder when patrolling in the open.

Keep in mind that these fish require unusually high water temperatures, making it difficult to find compatible tankmates. The higher temperatures also make the fish more prone to cotton wool disease and other bacterial infections. So, always assess your discus’ health status to prevent that.

Congo Tetras

Congo tetras should be one of your go-to mid-dwellers thanks to their easy-going attitude and adaptability to community tanks. These fish grow up to 3.5 inches, enjoy group living, and require at least 30 gallons to thrive. The best temperature range for them is 73-82 °F which already makes them ideal for most community setups.

Congo tetras are silvery with an orange band covering their bodies’ mid-section from head to tail. They also have orange heads with black eyes for a beautiful contrast.

These are peaceful fish, so always pair them with species that share their temperament, size, and feeding habits.

Bottom-Dwelling Fish

Bottom dwellers are more than just some pretty faces. They generally rank as cleaner fish, as they act as scavengers, collecting food, detritus, and general organic matter that they consume as food. Some bottom dwellers are more peaceful than others and impact their environment differently.

Let’s look at the most popular species for a clearer perspective on the matter.

Bristlenose Pleco

It was only natural that we were going to start with the most notorious bottom dweller. Bristlenose plecos typically grow up to 5 inches and can adapt to any community setup thanks to their peaceful demeanor and increased adaptability.

A typical pleco requires approximately 40 gallons of space and can thrive in temperatures around 73-81 F. This is a scavenger fish, so expect it to be on a constant lookout for feeding opportunities. Go for a planted aquarium with a variety of hiding spots to keep your pleco safe and comfy.

I recommend a sand substrate to protect the pleco’s sensitive barbels during its many food-seeing incursions.

These are peaceful and shy fish, for the most part, and require the presence of like-minded tankmates. Just make sure you don’t have more than one adult pleco per tank. These fish will get quite territorial towards each other as they age.

Red-Tail Shark

The red-tail shark is a different breed of bottom dweller. This black and red Cypirinidae comes with a sparkly temperament and a unique presence. Red-tail sharks can reach 6 inches and live up to 8 years in ideal conditions. These fish are very active and territorial, so you need at least 55 gallons for one specimen.

This is an active and explosive swimmer with a similar temperament. Red-tail sharks rank as semi-aggressive and territorial, as they don’t accept the presence of any other bottom dweller in their area. You can mitigate their aggressive tendencies by decorating their tank with live plants and various hiding spots.

Aim for 72-79 °F water temperatures and a rocky substrate to mimic the fish’s natural habitat. A well-oxygenated environment with clean waters is necessary to keep the fish happy and healthy over the years.

As an interesting fact – despite their notoriety as bottom dwellers, red-tail sharks are known to jump out of the tank at times. This can happen during their occasional incursions to the water surface.

Geophagus Cichlid

Cichlids are notoriously territorial and violent, but this isn’t the case with the Geophagus cichlid. This peaceful cichlid can reach 11 inches in captivity, with males being significantly larger than females. You need at least 55 gallons for one specimen to avoid stress and keep your cichlid in good spirits.

The Geophagus cichlid is quite a handsome one with its large head, big eyes, and the color gradient covering the entire body. Geophagus cichlids showcase a variety of colors and combinations, typically with spotted patterns and rainbow-like tints.

Aim for temperatures in the 76-84 °F range, as cichlids require slightly higher temperatures for proper digestion. Water quality is also important to prevent health problems and stress, which are typical for cichlids housed in improper conditions.

Since this is a sand-sifter fish, stick to fine sand as substrate.

Naturally, these are but 3 of the numerous bottom-dwelling species available, so don’t take this list as comprehensive. Depending on your setup and goals, you can also go for Corydoras catfish, loaches, other types of cichlids, and plenty of other species.

Tips for Stocking Your Fish Tank

Now that you know some of the options at your disposal, let’s get into the art of stocking your fish tank properly. Here are the core factors to consider:

  • Species compatibility – This is undoubtedly the first thing to consider. Your fish should not only share the same environmental requirements but be compatible to one another as well. You don’t want to pair peaceful and small fish with large and aggressive ones for obvious reasons. You also don’t want to house predatorial species with their natural prey for even more obvious reasons. Always do your research carefully in this sense.
  • Proper space – I know that overstocked tanks look better, but they’re also more unstable and difficult to maintain. Overcrowding your fish will increase the fish’s stress and aggression, leading to constant tensions and increased territorial behaviors. It will also destabilize the water chemistry due to the excess food residues and fish waste, causing ammonia and nitrites to spike. Always make sure that your fish have sufficient space based on their species’ requirements.
  • Proper care – This is an even more sensitive topic, and I’ll explain why. Different fish species are different; this goes without saying. This means that they have specific feeding habits, temperaments, and layout needs, and you need to accommodate all of them individually. For instance, top dwellers tend to eat all of the food before bottom dwellers can reach it. Other fish love open swimming spaces, while others require hiding spots and plants more. Make sure you can adapt to each species’ requirements for optimal results.

Plus, you should always make sure that your fish don’t fight with each other, no matter how compatible they seem on paper. After all, fish are all different individuals with different personalities, so always be prepared for that.


There’s no denying that community tanks are more rewarding in terms of aesthetics and overall impact, but they’re also trickier to pull out right. Fortunately, today’s article is the solution to your problems.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.

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