Red Acarichthys heckelii (Threadfin Acara)

The Red Acarichthys heckelii, commonly known as the Threadfin Acara, is a beautiful South American cichlid with stunning colours, flowing fins, and a peaceful personality. They are a great choice for aquarists looking for a larger feature fish without the aggressive behaviour often associated with bigger cichlids.

Once settled into a suitable aquarium, Threadfin Acaras are hardy, curious, and full of personality. They will often become quite confident and can even learn to recognise their owner at feeding time!

Here's a simple guide to keeping them happy and healthy:

Tank Setup

Tank Size: We recommend a minimum of around 240 litres for a single fish or pair. Bigger is always better, especially if you would like to keep a few together or add other fish.

Substrate: Fine sand or smooth gravel works well. They enjoy exploring the bottom of the aquarium and may gently sift through the substrate looking for food.

Decorations: Give them a combination of open swimming areas and places to explore. Driftwood, rocks, caves, and plants all make great additions. Don't worry about creating a perfect setup — as long as they have some cover and plenty of swimming space, they'll be happy.

Water Conditions

Threadfin Acaras are fairly adaptable as long as the water is clean and stable.

Temperature: 22–28°C

pH: 6.0–7.5

Hardness: Soft to moderately hard water, around 2–15 dGH.

Filtration: A good-quality filter is recommended. You don't need an extremely powerful current — a steady flow that keeps the water clean is perfect.

Water Changes: A 25–30% water change once a week is a good routine. Keep ammonia and nitrite at 0 ppm and try to keep nitrate below 20–30 ppm.

The most important thing is stable, clean water rather than trying to achieve perfect numbers.

Diet

Threadfin Acaras are easy to feed and enjoy a varied diet.

Good options include:

• Quality cichlid pellets or granules.
• Sinking pellets or wafers.
• Frozen foods such as bloodworms, brine shrimp and daphnia.
• Occasional vegetables such as blanched spinach, zucchini or peas.

Feed them once or twice a day, giving them an amount they can finish within a few minutes.

A varied diet will help keep them healthy and bring out their beautiful colours.

Tankmates

One of the best things about Threadfin Acaras is their generally peaceful temperament.

They can be kept with other peaceful fish that are large enough not to be considered food.

Good tankmates can include:

• Larger tetras.
• Peaceful South American cichlids.
• Larger catfish.
• Plecos.
• Peaceful barbs.
• Other similarly sized, peaceful community fish.

As with any community aquarium, avoid aggressive fish or species that constantly nip at fins.

Remember that Threadfin Acaras can grow quite large, so choose tankmates with their adult size in mind.

Behaviour and Personality

Peaceful: Threadfin Acaras are generally calm for a cichlid of their size. They may occasionally become territorial, especially when breeding, but they are not usually aggressive bullies.

Active: They enjoy exploring their aquarium and will happily use all levels of the tank.

Curious: Once they settle in, they often become very confident and will come to the front of the aquarium when they see you.

Social: They can be kept alone, as a pair, or in a suitable group. If keeping more than one, make sure the aquarium is large enough to give everyone plenty of room.

Health

Threadfin Acaras are generally hardy fish when given good water quality and a suitable aquarium.

Like most aquarium fish, they can become susceptible to problems such as ich or bacterial infections if they are stressed or the water quality deteriorates.

The best way to keep them healthy is simple:

• Keep the water clean.
• Don't overcrowd the aquarium.
• Feed a varied diet.
• Avoid sudden changes in water conditions.
• Give them plenty of space.

You don't need to be an expert to keep them successfully — consistency is the key.

Breeding

Threadfin Acaras can breed in the home aquarium when they are comfortable and well cared for.

A bonded pair may choose a sheltered area, cave, or suitable surface to lay their eggs. During breeding, they may become a little more territorial, so giving them plenty of space and hiding places is helpful.

If you're not specifically looking to breed them, there's no special setup required.

Overall

The Red Acarichthys heckelii (Threadfin Acara) is a fantastic choice if you're looking for a larger, peaceful and eye-catching cichlid.

Their size means they need a decent-sized aquarium, but they aren't a fish that requires complicated care. Keep their water clean and stable, give them plenty of swimming space, feed them a varied diet, and provide a few places to explore — and they should settle in nicely.

They're a great option for aquarists who want a big fish with a big personality, without the big attitude!

Interesting Fact

Threadfin Acaras get their name from the beautiful thread-like extensions on their fins. As they mature, these flowing fin extensions can become particularly impressive, giving the fish a graceful appearance as they move around the aquarium.