Many beginners embrace the X-ray tetra in their early days, but have you ever considered making these fabulous community fish a breeding project?
GABOR HORVATH Aquarist and breeder Gabor has an enviable eco-friendly fish house in Wales.
I ADORE QUIRKY FISHES. If a fish has an unusual body shape, finnage or colour, you can bet that I’m interested. Most of the time I need to search high and low to find that ‘special one’ but the subject of this article isn’t elusive at all. Quite the opposite: it would be more difficult to find a shop that doesn’t stock X-ray tetra. So why am I writing about a common, bread-and-butter fish? Read on and you will find out.
The X-ray tetra, Pristella maxillaris, had been the only representative of the Pristella genus for a long time. Its unique feature of having numerous conical teeth along the maxilla (hence the maxillaris moniker) was used to define Pristella.
The genus was long considered to be a monotypic taxon with only one species but after the discovery of P. ariporo in 2019 and P. crinogi in 2021 there are now three small tetras included in the genus. Interestingly the new additions don’t have those conical teeth, so the genus was redefined, using 15 synapomorphies (shared characteristics inherited from a common ancestor).
Older readers may recall a name of Pristella riddle—that’s a now obsolete synonym to P. maxillaris.
The Pristella name itself refers to the diminutive size as none of the above species grow larger then 4-4.5cm. The two newly discovered species aren’t present in the trade (yet). On the other hand, Pristella maxillaris has been around for many decades and became one of the staples of the aquarium hobby.
Farmed or wild?
X-rays are undemanding and relatively easy to breed, so producing them in mass causes no issues. Due to the good availability of cheap captive-bred stock you won’t find wild caught specimens in the shops (there is simply no demand for them), but that means that the fish you can actually buy are well-adapted to life in captivity and will easily fit into many communities. If you really want to dig in and find out more about their origin then the wild flocks inhabit coastal river drainages and swamps in several South American countries, from Venezuela to Brazil. Due to the ever-changing nature of these habitats, they often meet waters with various levels of changing acidity, alkalinity and salinity, though despite the fact that the X-ray tetra can tolerate some salt i
