5 Practical Tips To Keep Oscar And Jack Dempsey Fish Together

Jack Dempsey fish in a tank with oscar fish

Many aquarists looking for a large fish will think of keeping the Oscar or Jack Dempsey cichlid. But can Oscar and Jack Dempsey fish live together?

Yes, Oscar and Jack Dempsey fish can live together. However, both these freshwater cichlid species can be highly aggressive. Therefore, conditions like aquarium size, the environment inside the tank, fish size, and tankmates must be ideal for both these fish to stay together.

Let’s now understand how to keep Oscar and the Jack Dempsey fish together in more detail.

How To Keep Oscar And Jack Dempsey Fish Together?

Keeping two aggressive fish like Oscar and Jack Dempsey cichlids will not be a straightforward task.

Given below are some tips on creating a harmonious tank for these two cichlid species.

1. Spacious Tank

The size of the fish tank is extremely critical for keeping large fish with an aggressive temperament.

A minimum tank size of 90 to 100 gallons is required to house aggressive fish.

It’s important to understand that inadequate space will increase aggression in both the Oscar and Jack Dempsey fish.

So a large tank is required to ensure both have enough space inside the tank.

2. Plenty Of Hiding Places

Cichlids inhabit waters containing dense vegetation in the wild.

So both the fish prefer planted aquariums that replicate their natural habitat.

Adding aquatic plants, wood, and decorations mimics the fish’s natural environment and creates plenty of hiding places inside the aquarium.

Besides, the cover will reduce the interaction between the Oscars and the Jack Dempsey fish and allow them enough time to rest.

It will also make the fish feel calm and secure.

3. Fish Age And Size Must Be Similar

To keep two aggressive fish species together, you must consider their size and age, among other factors.

The Oscar and Jack Dempsey fish are fierce and devour everything that can fit in their mouths.

However, if both these fish are of the same size and age, they can withstand each other’s aggression.

Keeping fish fry with either of these adult carnivores will result in the fry becoming their snack.

Therefore, the size of both the cichlid species must be similar.

4. Use A Divider To Separate The Tank Space

Jack Dempsey fish are vicious and will nip, chase, and bully other fish.

However, Oscars are fierce and will, in most cases, stand their ground.

So you will notice a lot of aggression and confrontations inside the tank.

Therefore, it’s best to use a divider to separate the fish. It will also ensure peace and harmony inside the tank.

5. Keep A Spare Tank Ready

After trying hard to create a favorable environment inside the tank, you may still notice some unnecessary displays of aggression and standoffs between these cichlid species.

A spare tank can help in such cases to isolate both the species and avoid any unpleasant incidents.

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Can Oscar And Jack Dempsey Fish Breed?

Yes, Oscar and Jack Dempsey fish can breed together; having hybrids is expected in the cichlid hobby.

Two fish species that live in the wild together will not hybridize, but they will readily do so in an aquarium.

New research indicates that a female cichlid will mate with a species from another group if the male’s coloration is sufficiently attractive or if the female can’t see the male due to poor lighting conditions.

Besides, cichlids are a large and diverse group of primarily freshwater fish with more than 1600 different species and are much more likely to remain undiscovered.

Tank Setup For Oscar Fish

Oscar fish are large fish that inhabit the freshwaters of the Amazon.

So it’s essential to consider their size and other factors of their natural environment.

Given below are some of the requirements that you must consider while setting up a tank for the Oscar fish.

1. Tank Size

Oscar fish tank

The size of the aquarium is an essential factor to consider when keeping larger fish species.

Oscars can grow up to a foot long and need a large aquarium of at least 55 gallons for a single adult fish.

The aquarium should be larger if you intend to keep more than one Oscar fish.

A general rule is that you must add 20 to 30 gallons of water for each additional Oscar Fish.

The tank shape is also equally important.

A wide tank will be better than a tall one as it provides the fish with more horizontal swimming space.

2. Water Parameters

The ideal water temperature for Oscar fish is in the range of 74°F to 81°F (23.3°C to 27.2°C).

You will also need to maintain a pH of 6 to 8 and water hardness of about 5 to 20 dH.

Oscar fish are highly sensitive to temperature variations.

So, using a thermometer will help to maintain a suitable water temperature.

You can also use a water conditioner to reduce the water hardness.

3. Aquatic Plants, Decor, And Substrate

Oscar fish need a tank having a soft, sandy bottom with vegetation, debris, and stones scattered on top.

Choose fine gravel so that it doesn’t hurt the fish.

Hornwort and floating plants are excellent for Oscar fish tank.

Live plants such as Java Fern and Java Moss can also be used to create an underwater environment.

4. Tank Maintenance

Oscar fish are sensitive to the presence of ammonia and nitrites.

It’s important to cycle the tank before adding them to the new tank.

Regular tank maintenance is essential, with a minimum water change of 20% every 15 days.

Cleaning the decorations and substrate is also vital to avoid the accumulation of dirt and debris.

Tank Setup For Jack Dempsey Fish

Jack Dempsey fish live in slow-moving waters, including lakes, streams, canals, and wetlands.

So, creating a similar environment in captivity will make them comfortable.

Given below are some of the requirements that you must consider while setting up a tank for the Jack Dempsey fish.

1. Tank Size

Jack Dempsey fish needs a lot of space inside the tank. So the tank size to keep a single fish is 80 gallons.

Every additional fish will need at least 50 gallons of extra water.

Jack Dempsey cichlids also need a lot of space to grow.

Keeping them in a small tank can stunt their growth and make them less active.

2. Water Parameters

The ideal water temperature for Jack Dempsey fish is between 72°F to 86°F (22°C to 30°C), with a pH of 7 to 20 and water hardness around 9 to 20 dH.

Jack Dempsey fish are hardy and can survive some temperature variation.

However, these tropical freshwater fish like warmer temperatures.

So a thermometer can help in maintaining the ideal water temperature.

3. Aquatic Plants, Decor, And Substrate

Choose a sandy, muddy substrate that resembles the substrate in the native habitat of Jack Dempsey fish.

Vegetation is also important in a Jack Dempsey aquarium.

Floating and deep-rooted plants like Anubias or Java Fern can be used because their rhizoids adhere firmly to the surface and don’t come off easily.

You can use caves and castles to create hideouts for the fish.

Hollow decorations will also help them feel comfortable and secure inside the tank.

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4. Tank Maintenance

It’s vital to ensure that the water is free of excess nitrates and phosphates to keep Jack Dempsey fish healthy.

You should replace at least 20 percent of the water in the tank every two weeks, especially when there are lots of fish in the tank.

When cleaning your aquarium, always use a gravel cleaner.

Most problems associated with tropical aquariums usually stem from decaying organic matter.

It’s therefore essential to eliminate any leftover and decaying matter to avoid toxic buildup.