Pristella Tetra
Pristella maxillaris
Also known as X-Ray Tetra, Water Goldfinch
Edited by Ivan F. · Reviewed
Beginner verdict
A see-through little tetra with yellow, black and white fins, sometimes called the X-ray fish. It is very peaceful and adaptable to most water, which makes it a dependable beginner choice. It simply cannot compete with boisterous fish, so choose its companions with care.
Care at a glance
- Min tank size
- 14 US gal
- Footprint
- 24 x 12 in
- Temperature
- 72–82 °F
- pH
- 6–7.5
- Hardness
- 2–20 dGH
- Swim zone
- Mid-Water
- Min group
- 6 or more
- Lifespan
- Not well documented
Pristella Tetra tank mates and swim zone
Mid-Water
Spends most of its time in this part of the tank.
Poecilia reticulata
Poecilia wingei
Xiphophorus maculatus
Xiphophorus hellerii
Poecilia sphenops
Trichogaster chuna
Boraras brigittae
Chili Rasbora is small and shy, and is easily outcompeted for food by Pristella Tetra.
Tanichthys albonubes
Their temperature ranges barely overlap, so you will have little room for error.
Betta splendens
Betta often does best alone. Only try this in a larger, planted tank, and watch closely.
Ancistrus cirrhosus
Bristlenose Pleco is much larger than Pristella Tetra and may frighten or even eat it.
Carassius auratus
Goldfish suit cooler water and are not suited to tropical tanks, so Pristella Tetra is a poor match.
Pristella Tetra feeding and care
How to feed
- Feed small flakes and micro pellets, which it takes readily.
- Add small live or frozen foods such as daphnia for the best condition.
- Feed small portions you can see finished within a couple of minutes, because overfeeding fouls the water fast.
Telling males from females
Mature females are usually bigger and noticeably stockier than males.
Pristella Tetra care mistakes to avoid
- Do not buy just one or two. Keep at least 6 fish so they feel secure.
- Avoid boisterous or much larger tank mates, which it cannot compete with.
- Do not keep it under harsh light without plants, or it will spend the day hiding.
- Keep the school together, because a small group becomes nervous and pale.
- Check your tank before you buy. Our sourced minimum is 14 US gallons.
Pristella Tetra tank setup
A forgiving setup with room for a small community.
TankAt least 14 US gal (54 L), 60 x 30 cm
The smallest tank our sources give for Pristella Tetra. We list only tanks that hold this volume (allowing 10%, so a standard size counts) and have at least this much floor.
Aqueon Standard Glass Aquarium 20 Long US
Aqueon Standard Glass Aquarium 29 Gallon US
Eheim clearTank 73 Spain
Why we chose these (Best 20-Gallon Fish Tank: 20 Long or 29?). Nobody here has used or tested them.
Starter kitA kit with the tank, filter and light in one box
We list only kits whose tank fits Pristella Tetra, up to twice its minimum volume. A kit whose heater has a fixed setting shows only when that setting is inside Pristella Tetra's temperature range.
Tetra Complete LED Aquarium Kit 20 Gallon US
Check the heater's setting
Tetra Starter Line LED Aquarium 54 L Spain
Heater preset to 25 °C
Tetra Starter Line LED Aquarium 80 L Spain
Heater preset to 25 °C
Why we chose these (Best Aquarium Starter Kit: What to Look For). Nobody here has used or tested them.
FilterHang-on-back or large sponge filter
Easy to maintain and strong enough for a community without blasting the fish.
Seachem Tidal 55 Power Filter US
Marineland Penguin PRO 175 Power Filter US
Eheim LiBERTY 130 Hang-on Filter Spain
Seachem Tidal 35 Power Filter Spain
Why we chose these (Best Filter for a 20 to 29-Gallon Tank). Nobody here has used or tested them.
HeaterKeep it at 72–82 °F (22–28 °C)
Adjustable heater, about 5 W per gallon: 100 W at 20 gallons, about 150 W at 29. Enough power to hold a stable temperature in most homes. Size up for a cold room.
Aqueon Pro Adjustable Heater 100 W US
Aqueon Submersible Glass Heater 100 W US
Eheim Thermocontrol e 100 Heater Spain
Tetra HT 100 Electronic Heater Spain
Why we chose these (Best Heater for a 20 to 29-Gallon Tank). Nobody here has used or tested them.
Water conditionerDechlorinator such as Seachem Prime
Tap water contains chlorine or chloramine that harms fish.
Seachem Prime US
Fritz Complete Water Conditioner US
API Betta Water Conditioner US
sera aquatan Spain
Tetra AquaSafe Spain
Sold at Kiwoko · Sold at Tiendanimal · Sold at zooplus.es · Maker's details
Why we chose these (Best Water Conditioner for Betta Fish). Nobody here has used or tested them.
Test kitLiquid kit such as API Freshwater Master
Tracks ammonia, nitrite, nitrate and pH while the tank cycles.
API Freshwater Master Test Kit US
API General & Carbonate Hardness Test Kit US
See it at The Shrimp Farm (a retailer; affiliate link) · Sold at Bulk Reef Supply · Maker's details
sera aqua-test box (Cl) Spain
JBL PROAQUATEST COMBISET Plus NH4 Spain
Why we chose these (Best Test Kit for a Freshwater Aquarium). Nobody here has used or tested them.
SubstrateAdaptable and does well in most tanks; river sand suits a biotope setup.
We are still choosing products for this.
Hiding places and decorLooks best heavily planted; driftwood and dried leaves complete a biotope.
We are still choosing products for this.
PlantsSafe with live plants
Cycle the tank before adding animals. See our guide on how to cycle a fish tank.
Where to buy Pristella Tetra
We have not found a store that sells Pristella Tetra under its scientific name yet. We add stores as we confirm them.
Live animals and plants travel by courier. Check the store's live-arrival guarantee, and only buy once your tank has cycled (see how to cycle a fish tank).
Some US states restrict certain species. Check our US state aquarium rules table and your state's own rules before you buy.
Pristella Tetra FAQ
What size tank do Pristella Tetras need?
Our sourced minimum is 14 US gallons (54 liters), with a footprint of 60 x 30 cm. A bigger tank is always easier to keep stable.
How many Pristella Tetras should I keep?
Keep at least 6 fish. Bigger groups usually look better and behave more confidently.
What can live with Pristella Tetras?
Good matches on our list include Fancy Guppy, Endler's Livebearer and Platy. Avoid Goldfish.
How long do Pristella Tetras live?
Lifespan is not well documented for this species. Stable water and a good diet help any animal live longer.
Why is it called the X-ray tetra?
Its body is so translucent that you can see its spine and organs through its sides, like an X-ray image.
Pristella Tetra facts and sources
- Family
- Characidae
- Native to
- Amazon, Orinoco and coastal Guiana rivers
- Adult size
- 1.8 in (4.5 cm)
- Temperament
- Peaceful
- Social needs
- Schooling/Shoaling (6+)
- Diet
- Micro-Predator
- Water flow
- Gentle
- Substrate
- Any
- Live plants
- Yes - Loves Plants
- Shrimp
- Adult Shrimp Only
- Fin nipping
- None
- Vulnerable to nippers
- No
- Breeding
- Moderate
Sources
- Seriously Fish: Tank size, water ranges and behavior
- FishBase: Cross-check of water ranges and size
Lifespans are approximate and come from aquarium care guides, because these databases rarely publish them.
Where sources differ, we show the Seriously Fish aquarium figures.
Spotted something wrong? Report a parameter correction. For a sick fish, see our veterinary disclaimer.