How do I keep these larger barbs?
I'd like to keep a group of filament barbs in a 120x45cm tank. My water is 7.4pH with moderate hardness. What would be the best way to filter this tank and how should I decorate and plant it to best reflect their natural habitat? What would be a good-sized group of these fish, and could you also recommend some good tank mates please?
PAUL MORRIS
NEALE SAYS: The delightful filament barb, Dawkinsia filamentosa, is one of those fish that really should be more widely kept. Although fairly large, with adults comfortably reaching 10-12cm in captivity, and supposedly up to 18cm in the wild, they have the merit of retaining their lovely colours even when fully grown, something that isn’t always true of the larger barbs and characins.
They are relatively peaceful fish, though potentially nippy, and as with many barb species, they are boisterous among themselves and unlikely to behave well if kept in too small a group. But if you keep at least six—but ideally ten or more—they generally settle down well and cohabit nicely with bottom-dwelling fish such as loaches and L-number catfish, both of which have the same sort of requirements.
These fish need a brisk water current and plenty of oxygen and a temperature of 24-25°C. I’d be looking at an external canister filter with a spray bar or even a Venturi valve to mix the outflow of water with the air, and thereby drive off any dissolved carbon dioxide while allowing more oxygen in. Plants you can grow attached to rocks and bogwood would be ideal, such as Java ferns. If you find algae a problem, undemanding but fast-growing species, such as larger Vallisneria, handle water currents well and are robust enough to do well alongside all but the more fish.
I’m not totally convinced a 120cm aquarium will be long enough for these active fish, however—particularly if you intend to add some medium-sized loaches or catfish too. Given the size of your tank, you’d be best ensuring the largest possible group of filament barbs to ensure they behave themselves, and if there’s space left over, perhaps add an interesting Garra species or a medium-sized L-number with the street smarts needed to keep out of the way. If you choose the latter, avoid the Rio Xingu species as these usually prefer warmer water than your Filament barbs, but the more commonplace species from the Amazon and Orinoco rivers should be fine.