X Ray Tetra (Pristella maxillaris) 2 cm

Overview

The X Ray Tetra (Pristella maxillaris) is a classic community fish loved for its delicate, translucent body and subtle yellow, black and red fin markings. At around 2 cm on sale, these are young fish with plenty of growing to do, maturing to a compact adult size of around 4.5–5 cm. They are a superb choice for planted aquariums and peaceful community setups, bringing constant movement and a calm, schooling presence to the middle water layers.

Despite their delicate appearance, X Ray Tetras are surprisingly adaptable and are often considered one of the hardier small tetras available. They do best in groups, where their confidence increases and their natural shoaling behaviour becomes more visible. Provide stable water conditions, regular maintenance and a varied diet, and they will reward you with active, long-lived display fish.

All fish are supplied with our live arrival guarantee and fast UK delivery, so you can order with confidence from Tropical Fish Co.

Care at a Glance

Origin & Natural Habitat

Pristella maxillaris is native to South America, with populations associated with the Amazon and Orinoco drainages as well as coastal river systems in northern South America. In the wild, X Ray Tetras inhabit slow-moving rivers, floodplains, blackwater and clearwater tributaries, and seasonally flooded areas with plenty of vegetation and leaf litter. These environments are typically warm, gently flowing and rich in cover, with dappled light filtering through overhanging plants and trees.

The species is well known for its adaptability to a range of water conditions, which is one reason it has remained popular in the aquarium hobby for so long. In nature, it forms shoals and uses group behaviour for security. Recreating that sense of cover and companionship in the aquarium is the key to seeing the best colour, confidence and activity from your fish.

Tank Setup & Water Parameters

A planted aquarium with open swimming space is ideal for X Ray Tetras. Aim for a tank of at least 60 litres for a small group, though a larger aquarium will always be more stable and allow a more natural shoal. A dark substrate, driftwood, live plants and floating cover can help bring out their colours and make them feel secure. Gentle filtration is preferred, with enough flow to keep the water clean but not so much that the fish are constantly battling current.

Water parameters should be stable rather than extreme. They are comfortable in a wide range, but the best results are usually seen in warm, clean water between 24 and 28°C, with a pH from 6.0 to 7.8. They tolerate a broad hardness range, making them suitable for many UK community aquariums. Regular partial water changes, sensible stocking and good filtration are more important than chasing exact numbers.

Because they are schooling fish, keep them in a group of at least six, with eight or more being even better. Larger groups reduce stress and encourage natural behaviour. Provide some shaded areas and planted margins, but leave the centre of the tank open for schooling movement. A secure lid is recommended, as active tetras may jump when startled.

Feeding Guide

X Ray Tetras are omnivores and will accept a wide variety of foods. A quality micro pellet or flake should form the staple diet, supplemented with frozen or live foods such as daphnia, baby brine shrimp, cyclops and bloodworm. Small, frequent feedings are preferable to large portions, as this helps maintain water quality and ensures all fish get a share.

For the best condition and colour, offer a varied diet that includes both protein-rich foods and some plant-based content. Feed only what the shoal can consume in a couple of minutes, once or twice daily. As with all aquarium fish, avoid overfeeding, and remove any uneaten food to keep the tank clean.

Tank Mates / Compatibility

X Ray Tetras are peaceful and make excellent community fish when housed with similarly calm species. Good tank mates include other small tetras, rasboras, peaceful barbs, Corydoras catfish, small plecos such as Ancistrus, dwarf gouramis, and other non-aggressive fish that will not outcompete them for food. They also work well in planted community tanks with shrimp, although very small shrimp fry may occasionally be picked off.

Avoid large, boisterous or predatory fish that may intimidate or eat them, including many cichlids, larger barbs, aggressive livebearer setups, and substantial catfish. Fin-nippers should also be avoided, as their flowing fins and constant schooling behaviour can make them easy targets. The best results come from calm, well-planned community aquariums with fish of similar size and temperament.

Compatibility note: X Ray Tetras are most confident when kept in a proper shoal. A lone fish or a pair will often hide and may become stressed, so group size is just as important as tank mate selection.

Why Buy from Tropical Fish Co

At Tropical Fish Co, we focus on supplying healthy, well-conditioned livestock with careful packing and reliable service. Our X Ray Tetras are selected for quality and vigour, and we aim to make the whole process straightforward from checkout to acclimation. With fast UK delivery and our live arrival guarantee, you can order with peace of mind.

We understand that live fish are a special purchase, so we take care to provide clear information, sensible husbandry advice and dependable customer support. Whether you are building your first community aquarium or adding to an established shoal, X Ray Tetras are a rewarding, attractive and low-maintenance choice that fits beautifully into a wide range of aquascapes.