Ctenops nobilis is regarded as one of the most difficult fish to keep. Matt Clarke explains its needs and suggests that you stear clear of it, unless you really know what you're doing...
Common name: Frail gourami
Scientific name: Ctenops nobilis
Origin: India - Assam, Bihar, Sikkim, north-east Bengal - as well as Bangladesh.
Habitat: Rivers and lakes that are rich in aquatic plant growth.
Water: Very soft, acidic water (pH 4-5) is usually recommended for this species. Use the Pearson's Square calculator on the PFK website to help you get water of the right chemistry by mixing tapwater with RO. Most people also keep these at a relatively high temperature. Amazingly, I have recently seen a very healthy shipment of these fish doing well in hard, alkaline water. Their importer, Tom Halvorsen, puts his success with the species down to keeping them at a lower temperature - only about 20C. This has to be worth a try if you're going to attempt to keep this very challenging species.
Aquarium: A well-planted species tank, or community of other small and peaceful acidophilic species. Rival males can be a little territorial with each other.
Breeding: Mouthbrooder. But rarely bred due to the difficulty of keeping it alive for long periods.
Identification: Protrusible upper jaw; denticulated pre-operculum; dorsal fin has four to six spines and six to eight branched rays; anal fin has four to five spines and 23-28 branched rays; 28-34 scales in the lateral series.
Similar species: Macropodus look vaguely similar, but on Ctenops, the dorsal is positioned above the anal fin rather than the pectorals.
Notes: In the opinion of many experts, including those who specialise in anabantoids, Ctenops nobilis is one of the trickiest of all freshwater fish to keep. I'd be nervous about trying to keep these, especially if they're only recently imported specimens. Don't bother trying unless you are experienced with difficult species...
Availability: Few shops are brave enough to order these as they are so fussy and so few of their customers are likely to have the skills required to keep them. We spotted a couple in a display tank at The Water Zoo, Peterborough, which had gone unsold in the fish section for several months.
Price: Expect to pay
This article first appeared in the August 2004 issue of Practical Fishkeeping magazine.