6 beautiful freshwater aquarium fish that grow so huge they need large tanks or ponds (Not for beginners)

While keeping aquarium fish needs a lot of effort, it's a deeply rewarding experience. However, not all fish are suitable for keeping in tanks-- while they are sold as juveniles that are only a few cms in size, some fish species are known to grow huge in size over time. And so, such fish need far more space than most tanks can provide. These giant fish are stunning to look at but come with special care needs, huge appetites, and unique behaviours that make them unsuitable for beginners. Here we list some such freshwater fishes:

One of the most majestic freshwater fish, Arowanas are known for their long, sleek bodies and graceful swimming style. They have dragon-like appearance, and so they are also commonly called dragon fish. But these fish can grow up to 3 feet long and hence, they need a big tank with proper lid, as they’re known to be strong jumpers. These fish are carnivorous and territorial, which makes keeping them challenging for beginners.

The Redtail Catfish is a South American species and it is famous for its bright red tail and massive size. It can reach over 4 feet in size in captivity. Considering their size, they need a big tank or a private pond to move around freely. And do note: Despite their gentle nature, they grow rapidly and will eat almost anything that fits in their mouths, including tank mates! So, choose their tank/ pond mates wisely.

Similar to Piranha, the Pacu is a peaceful, vegetarian fish. But they can grow up to 30 inches and weigh over 20 kilograms, which makes keeping and caring for them challenging for beginners! Unfortunately, many people buy them as “baby Pacus” without realising how large they get-- this leads to frequent abandonment.

As the name suggests, Giant Gourami can reach up to 24 inches in length. Native to Southeast Asia, these fish are quite intelligent and they can even recognise their owner. They are hardy and huge freshwater fish, and so they need huge tanks or ponds to move around freely.

Oscars are popular among fish keepers for their bright colours and personalities, but large varieties of this fish can grow up to 14–16 inches. And so, they need large tank and pristine water conditions to stay happy and healthy. These fish are also highly territorial, which makes them challenging for beginners.

A beautiful and popular pet fish, Koi come in a variety of colours. While these fish are quite small in their juvenile stage, they grow huge when they turn into adults. And so, these are usually kept in ponds.