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The Clown knifefish, Chitala ornata

Richard Hardwick, of Wharf Aquatics in Notts., takes a look at an easily-kept oddball which is often added to community tanks - with unfortunate results...

Copyright © Practical Fishkeeping

When it comes to graceful fish, few can match the effortless glide of the Clown knifefish around the aquarium - whether it's swimming forwards or backwards.

These fish originate from South East Asia where they live in large rivers and swampland and have evolved to breathe atmospheric air in conditions where oxygen is less plentiful. Although there are several species of knifefish, the Clown is unmistakable due to its attractive markings - a series of large black spots, ringed with silver along the body. The pattern of these rings can vary immensely from fish to fish.

They are very undemanding fish and make a good choice for both the novice and more experienced fishkeeper providing you realise their size potential. These fish prefer slow-moving water so I suggest using an external power filter with a spray bar to splash at the water surface rather than creating a current around the aquarium.

Greedy feeders
Clown knifefish are very greedy and consume large amounts of high protein foods (see fact file). This obviously produces high levels of nitrate from the breakdown of wastes through the filter, so I would suggest a 25% water change on a weekly basis.

My personal collection of Clown knifefish consists of four large specimens which I've managed to convert onto floating sticks that they greedily snatch from the water surface. To get these predatory fish to eat such foods they must be housed with fish that naturally feed from the surface such as large barbs.

Tankmates
These fish are best kept either singly or in groups of three or more. You can also keep them with catfish, such as Synodontis and medium-sized pims, Gars, Polypterus, large barbs and more peaceful large cichlids. Avoid aggressive cichlids like Oscars, Jaguars, Red devils and so on.

There are no real problems in keeping this fish - just remember that it is a highly predatory species and the size of its mouth is very deceiving. The most common mistakes made with Clown knifefish is that people buy them small for their community tank, only to find their other fish slowly disappear without an obvious culprit - this is due to the Clown knifefish's nocturnal feeding habits.

Fact file

Clown knifefish
Notopterus (Chitala) chitala
Size: Seldom grow bigger than 18" in captivity but be aware that they do have the potential to reach up to 1m or more in length, with a body depth of 15" and over.
Guide price: £6 - £10 for a 5" specimen and up to £80 for a 15-18" fish depending on the markings which are extremely variable.
Aquarium: 48" x 18" x 18" minimum for a single fish and 72" x 24" x 24" for three or four. Dim lighting is preferred with sand as a substrate, perhaps with some smooth boulders; densely-planted, with bogwood and beech branches.
Water parameters: A neutral pH of 7 is fine, with a general hardness of around 8, although neither is critical for the well-being of this species.
Temperature: 78-82°F.
Diet: As babies these fish often refuse to eat anything but live foods such as bloodworm and small fish, but with patience they can be persuaded to take chopped mussel, cockle and whitebait. Smaller specimens (4-6") are best fed twice a day but once they reach 12" or more, two large meals a week with sprats, cod and large garden worms etc. will suffice.
Breeding: Clown knifefish have bred in captivity, but to my knowledge only on a commercial basis - this is because in Thailand they are regarded as a food fish. They lay their eggs between May and July and the male looks after both eggs and brood.

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Richard Hardwick 594 (words, 8415 hits)
Published online: 11.07.02


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