The Best Fish For 100 Gallon Tank

Buying and maintaining a 100 gallons tank is not easy. It takes effort, requires patience, and most important, one must have the proper knowledge. Without having the correct information, taking care of a 100 gallons tank can become highly challenging. 

Along with tank and maintenance information, you must also know about the fish that can happily survive in such a big tank. Fortunately, this fish tank size lets you keep many wonderful fish species. 

Among the available 100 gallons fish options, you should consider housing Angelfish. The minimum tank requirement of this fish is 55 gallons. This fish species looks excellent, and it can comfortably live with tank makes that are large and calm. 

Besides this, there are many other fish recommended in this post. With beautiful fish, you can also add stunning decorations to make your fish tank look magical. 

List of Fish for 100 Gallons Tank 

When it’s a 100 gallons tank, you should be careful while choosing fish. If fish are too small, you would have to add multiple hiding places for them. And if you have selected a larger fish species, it might not be able to move freely. 

To make the fish selection process easy for you, we have listed some unique fish you can house in the tank. If you are searching for the best fish for a 3 gallons then don’t miss out our guide.

#1 Angelfish 


It’s a freshwater fish that is extremely popular among tank keepers because of its attractive shape. This fish comes in a variety of colors and patterns, which makes them even more popular. 

While housing Angelfish, avoid filling the tank with small fish because they could become a snack. Also, you must avoid keeping Angelfish with any aggressive fish or fin-nippers. 

It can grow to a good length but is a slow mover. This fish species is considered to be calm. However, they can get aggressive towards one another. 

Scientific name Pterophyllum
Maximum size 12 inches (tall)
Minimum tank size55 gallons 
Tankmates Medium-sized schooling fish, peaceful fish 
Tank setupLive plants, plenty of swimming space, river rocks 
Temperament Generally peaceful 

#2 African Leaf Fish 

African Leaf Fish

African Leaf Fish is another colorful fish that you can keep in the tank. When this fish is near rocks or plants, its pattern and color make it almost invisible. The fish uses this advantage to gulp prey. 

So, you should avoid keeping African Leaf Fish with any species that you don’t want to eat. Also, you must not keep it with any aggressive fish as it has a docile nature.

Most of the time, African Leaf Fish are also known as Leopard Bush Fish, Leopard Ctenopoma, Spotted Ctenopoma, and Spotted Climbing Perch. 

Scientific name Polycentropsis abbreviata
Maximum size 8 inches 
Minimum tank size55 gallons 
Tankmates Peaceful fish that is too large to eat
Tank setupLive plants and hiding spots
Temperament Semi-aggressive 

#3 Oscar 

Oscar Fish

These are comparatively larger and have an aggressive nature. If given proper care, they can live for around a couple of decades. That means housing an Oscar in the aquarium is a long haul. 

You can keep this fish in pairs, but it’s advised to house a single Oscar in a tank as it can get pretty aggressive. In simple words, this fish is a single tank specimen that needs lots of space to swim and some driftwood. 

Scientific name Astronotus ocellatus
Maximum size 15 inches 
Minimum tank size55 gallons (single-specimen tank)
Tankmates Other Oscars or you can keep it alone
Tank setupRiver rocks and plenty of space for swimming 
Temperament Aggressive 

#4 Silver Dollar

Silver Dollar fish

This fish appears to be small at first, but it can grow up to six inches under proper circumstances. It’s a peaceful fish species that does not like fighting, but it can munch up the live plants. 

It’s advised to house a bunch of Silver Dollar as this way they live happily. When you are housing a group of these fish, avoid keeping them in a massive tank, but a 100 gallons tank is perfect for them.  

Scientific name Metynnis argenteus
Maximum size 6 inches 
Minimum tank size100 gallons (school of 6)
Tankmates Medium-size fish that they can’t eat
Tank setupRiver rocks and plenty of space for swimming 
Temperament Peaceful 

#5 Butterflyfish 


Among the fish fit for housing in a 100 gallons tank, butterflyfish is the prettiest. Its dazzling color, shape, and pattern even make it a great centerpiece. 

Butterflyfish are suitable for fish tanks, and they need at least 75 gallons of water. That means they can survive nicely in a 100 gallons tank. This fish can be easily found around tropical reefs. 

Scientific name Chaetodontidae
Maximum size 12 to 22 cm
Minimum tank size75 gallons 
Tankmates Medium-size fish that they can’t eat
Tank setupPlenty of hiding spots made by rocks and corals 
Temperament Peaceful 

#6 Black Devil Catfish

Black Devil Catfish

It’s a highly territorial fish. That means you should carefully choose its tankmates. If any fish enters its marked territory, it will viscously bite it. 

When this fish is kept in a bigger tank, like a 200 gallons tank, it marks a great area as its territory. Also, in such a big tank, other fish learn to keep a distance from it. 

Scientific name Bagarius yarrelli
Maximum size 2m
Minimum tank size100 gallons 
Tankmates Alone 
Tank setupPlenty of hiding spots made by rocks and corals 
Temperament Aggressive 

How to effectively maintain a 100 gallons tank? 

Taking care of 100 gallons can feel like a hectic task if you don’t know the right way of doing it. But if you regularly change the water and clean the filter, the fish tank water would not get polluted. 

When the aquarium water is not polluted, fish can live happily in it. Also, it’s essential to avoid overfeeding the fish. That’s because overfeeding might kill the fish and pollute the tank. 

Also Read: Best 50 gallon fish tank


Keeping a 100 gallons tank is fun, only when you properly maintain it. For this sized tank, it’s essential to keep the water and surrounding clean. 

When searching for fish for this tank, consider their size. That’s because a bigger fish might not get enough place to swim, and a smaller one would need multiple hiding spots. 

Also, while housing different fish in a single tank, check their characteristics. It will help you pick better tankmates. 

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