Dinosaur Fish 101: Species, Tank Size &amp; Care Guide for 2026

Fluval FX6 Canister Filter·handles the heavy bioload these fish produce

Fluval Stratum or soft aquarium sand·prevents belly scrapes and skin infections from sharp gravel

Aqueon 75 Gallon Aquarium Kit·meets the minimum tank size these species need long-term

Tight-fit aquarium lid clips·stops the #1 cause of preventable dinosaur fish deaths

If you've ever stood in front of a pet store tank and locked eyes with a grey, armor-plated fish that looks like it swam straight out of the Jurassic period, you already know the appeal of a "dinosaur fish." But admiring one through glass and actually bringing one home are two very different things. This guide breaks down exactly which dinosaur fish you can buy, how big a tank they really need, and which species will outgrow your living room before the tank is even paid off.

Quick Answer: "Dinosaur fish" is a nickname for several ancient-lineage species sold in the aquarium trade — most commonly bichirs, gars, and reedfish — plus giant species like arapaima and sturgeon that quickly outgrow home tanks. Most beginner-friendly dinosaur fish need at least a 55-75 gallon tank and cost $15-$60 per fish. None of them are literal dinosaurs — dinosaurs were reptiles, not fish — but some have barely changed in over 400 million years 1.

What Makes a Fish a "Dinosaur Fish"?

"Dinosaur fish" isn't a scientific name — it's a nickname aquarists use for species whose body shape has barely changed in tens of millions of years. If you're new to this hobby, that's the first confusion to clear up: no one is legally selling actual dinosaurs. What they're selling are fish from ancient lineages that predate most modern bony fish by a huge margin.

Bichirs, for example, belong to a fish family that appeared before many dinosaurs even existed 2. They still have lung-like structures and can gulp air at the surface, a trait that has stuck around since prehistoric times.

Common Myth: "Dinosaur fish are basically living dinosaurs, so they must be wild-caught and endangered." Reality: Most dinosaur fish sold in stores today, like bichirs and reedfish, are commercially bred in large numbers and are not endangered or illegal to own.

That myth matters if you're a first-time buyer worried about doing something wrong. In most of the U.S., these species are perfectly legal, farm-raised, and shipped to local fish stores like any other tropical fish.

Real Dinosaur Fish Species You Can Actually Buy

Five species make up almost every "dinosaur fish" sold in the aquarium trade. Each one has a very different adult size, so this is the section to read carefully before you buy.

Bichir (Polypterus species): Snake-like body, bony armor, and tiny leg-like fins. Grows 12-24 inches depending on species.
Reedfish (Erpetoichthys calabaricus): A slimmer bichir relative, sometimes called the "snakefish." Stays closer to 12-20 inches.
Spotted gar and longnose gar: Long, torpedo-shaped bodies with a duck-like snout full of teeth. Reach 2-3 feet in a large tank or pond.
Sturgeon: Cold-water fish with rows of bony plates called scutes. Most species need outdoor ponds, not indoor tanks, once mature.
Arapaima: A giant Amazonian air-breather that can exceed 6 feet in length — far too large for any home aquarium.

New to setting up a tank for something this different? Check out our beginner's buying guide →

Dinosaur Fish Species Comparison Table

Bichirs and reedfish are the only two dinosaur fish species most home aquarists should consider. The rest either need a pond, a public aquarium, or years of experience with oversized setups. Here's how the main options stack up.

Species	Adult Size	Min. Tank Size	Difficulty	Typical Price	Home-Tank Friendly?
Bichir	12-24 in	55-125 gal	Beginner-intermediate	$15-$50	Yes
Reedfish	12-20 in	40-75 gal	Beginner	$20-$40	Yes
Spotted gar	2-3 ft	125+ gal	Intermediate	$25-$60	Only in large tanks
Sturgeon	3-6+ ft	Pond only	Advanced	$30-$100	No
Arapaima	6+ ft	Public aquarium only	Expert	$100+	No

Recommendation: for a first dinosaur fish, choose a bichir or reedfish. Both stay a manageable size, tolerate average home water temperatures, and are widely available.

Tank Setup: Size, Filtration, and Water for Dinosaur Fish

If you're worried your tank is too small, you're probably right — most dinosaur fish outgrow starter tanks fast. A 10-gallon setup that works great for fish for a 10 gallon tank simply won't hold an adult bichir or gar. Plan for the adult size, not the size the fish is when you bring it home.

Here's what a bichir or reedfish actually needs:

Tank size: At least 55 gallons for one adult bichir; 75+ gallons if you're keeping more than one.
Filtration: A canister filter rated for double your tank's volume, since these fish produce a lot of waste.
Substrate: Soft sand, since bichirs root along the bottom and can scrape themselves on sharp gravel.
Lid: A tight-fitting lid is non-negotiable — bichirs are strong jumpers and escape through tiny gaps.
Temperature: 75-82°F, with a stable pH between 6.5 and 7.5.

Pro Tip: If you're setting this up in a rental, check your lease before buying a 75-gallon tank — the added weight (roughly 850 pounds filled) can matter to landlords, unlike smaller starter tanks.

Compatibility is another common worry for new keepers. Bichirs generally leave larger, calm tankmates alone, similar to the peaceful community approach used in an angelfish care guide, but they will eat anything small enough to fit in their mouth.

Feeding Your Dinosaur Fish

Dinosaur fish are predators, and their feeding needs are simpler than most beginners expect. Bichirs and gars are ambush feeders that rely on smell more than sight, since their eyesight is relatively weak.

A varied diet keeps them healthiest:

Sinking pellets made for carnivorous bottom feeders, like the Hikari Carnivore Sinking Pellets on Amazon, as a daily staple.
Frozen or live foods such as shrimp, bloodworms, or earthworms, offered 2-3 times a week.
Occasional feeder fish only from a trusted, disease-free source, since wild-caught feeders can carry parasites.

Feed adult bichirs once daily; younger fish do better with small meals twice a day. Overfeeding is a fast way to foul the water in a tank that's already producing heavy bioload.

Need to keep startup costs down? See our budget-friendly gear picks →

Common Mistakes First-Time Dinosaur Fish Keepers Make

Most dinosaur fish problems trace back to buying on impulse without planning for adult size. These are the mistakes keeper communities report most often.

Buying a juvenile without researching adult size — a 3-inch bichir at the store can become a 20-inch fish within two years.
Skipping the lid — bichirs and gars are notorious jumpers, and a fish found dry on the floor is one of the most common losses reported by new keepers.
Using sharp gravel — bichirs rub their bellies along the substrate and can develop skin infections from rough surfaces.
Mixing with fish too small to be safe — anything that fits in a bichir's mouth is potential food, not a tankmate.
Underestimating filtration needs — these fish produce far more waste than tetras or bettas of a similar tank size.

Pro Tip: If your dinosaur fish stops eating for a few days after arriving home, don't panic — mild stress-related fasting for 3-5 days after transport is normal and usually resolves on its own.

Are Any Dinosaur Fish Actually Extinct Species Brought Back to Life?

No aquarium dinosaur fish is a literal resurrected fossil, but one wild fish comes close: the coelacanth. Scientists believed coelacanths went extinct alongside the dinosaurs, until a living one was caught off South Africa in 1938 3. That single discovery is why the phrase "dinosaur fish still alive" gets searched so often.

Coelacanths are not sold in stores and cannot legally be kept as pets — they're deep-sea fish protected under international conservation agreements. As of 2026, researchers continue studying their genetics to understand how closely they relate to the ancestors of land animals 4. Genomic comparisons published in an August 2026 review show coelacanth DNA changes at an unusually slow rate compared to most fish 5, which helps explain why the species looks nearly identical to fossils millions of years old.

Bichirs, gars, and other aquarium "dinosaur fish" are a much more practical way to bring that ancient-lineage look into a home tank. For further reading on ancient fish lineages, NIH-indexed research covers how these body plans survived multiple mass extinctions.

Where to Buy Dinosaur Fish (and What They Cost in 2026)

Most beginner dinosaur fish sell for $15 to $60, and availability depends heavily on where you shop. Big chains like PetSmart occasionally stock small bichirs, but selection and health can vary by location. Independent local fish stores (LFS) typically offer better-conditioned stock and staff who can answer size and compatibility questions directly.

Online specialty retailers are usually the most reliable source for less common species, like specific bichir color morphs. As of August 2026, expect shipping costs of $25-$45 on top of the fish price for online orders, since these fish require insulated, temperature-controlled packaging.

Local fish stores: Best for seeing the actual fish and its health before buying.
Big-box pet stores: Convenient, but selection of true dinosaur fish is inconsistent.
Online specialty sellers: Best for rare bichir species, with added shipping cost.

New to bringing home your first oddball species? Start safely with our beginner's tank guide →

Conclusion

Dinosaur fish bring a genuine prehistoric look into a home aquarium, but only a couple of species — bichirs and reedfish — actually fit in a typical house. Plan for adult size and filtration before you buy, skip the sharp gravel, and always use a tight lid. Get the tank size right from day one, and a dinosaur fish can be one of the most rewarding oddball pets in the hobby.

Sources

Recommended Gear

Hikari Carnivore Sinking Pellets

formulated for carnivorous bottom feeders and won't cloud water like flakes

Fluval FX6 Canister Filter

handles the heavy bioload these fish produce

Fluval Stratum or soft aquarium sand

prevents belly scrapes and skin infections from sharp gravel

Aqueon 75 Gallon Aquarium Kit

meets the minimum tank size these species need long-term

Tight-fit aquarium lid clips

stops the #1 cause of preventable dinosaur fish deaths