This reviewed buying guide covers 10 freshwater fish. A photograph appears only when the image shows the exact species alive in an aquarium or other suitable submerged setting and its reuse record is complete; the reviewed profile remains available without substitute imagery while a qualifying photo is sourced.
Use the guide at the retailer to compare breathing, posture, body condition, skin, fins, eyes, and behavior with what is normal for the species. Look at the whole sales system, ask about feeding and recent arrivals, and quarantine every new fish before it shares water or equipment with an established aquarium.
This is an observation guide, not a diagnosis. A fish that looks healthy can still carry pathogens, while transport, lighting, age, sex, and social position can change normal appearance and behavior.
Content transparency
AI-generated draft, human-reviewed publication
This guide was drafted with generative AI used to organize research and prepare an initial version. The AI output was not treated as an authority or source. Dan from the Simply Submerged Aquatics team reviewed the published guide for accuracy and completeness within the scope recorded below.
What the human review covered
- Species identities, scientific names, and public fish-selection copy
- Healthy signs, purchase warning signs, and diagnostic limitations
- Species-normal behavior and temperament distinctions
- Source records, image licences, and TankWise app statements
Key takeaways
- Watch the complete sales tank before choosing an individual fish.
- Compare breathing, posture, body condition, skin, eyes, fins, and response rather than relying on one sign.
- Allow for normal species behavior, including resting, hiding, schooling, feeding patterns, territorial display, and social position.
- Confirm the scientific identity and eventual aquarium needs before buying.
- Only approved exact-species aquarium photographs are shown; a reviewed profile remains available without an image when photography is pending.
- A healthy-looking fish still needs a suitable aquarium; compare it with your saved tank in TankWise before buying.
Store-side field guide
10 fish at a glance
Match the store label to the fish, then jump straight to its healthy and warning signs.
Freshwater AngelfishPterophyllum scalare
White Cloud Mountain MinnowTanichthys albonubes
Chili RasboraBoraras brigittae
Glass CatfishKryptopterus vitreolus
Threadfin RainbowfishIriatherina werneriRyukin GoldfishCarassius auratusGold Laser CorydorasCorydoras sp. CW010
Demasoni CichlidChindongo demasoniBanjo CatfishBunocephalus coracoideus
Rainbow ShinerNotropis chrosomusCheck the sales tank before the fish
Watch before anyone taps the glass, feeds the fish, or reaches for a net. Compare breathing, posture, body condition, skin, fins, eyes, and behavior across the group rather than choosing only by color or activity.
Pause if a tankmate is dead, unable to balance, extremely thin, ulcerated, heavily spotted, covered in growth, or breathing with pronounced effort. Ask when the fish arrived, whether it has eaten, and whether nearby tanks share filtration.
A feeding response is useful evidence, but it does not prove that a fish is disease-free. Quarantine every new arrival separately and avoid sharing wet equipment with the established aquarium.
- Observe the group from a distance before selecting a candidate.
- Compare the candidate with several fish of the same species when possible.
- Confirm the store label and scientific identity.
- Ask about arrival date, feeding, treatment history, and shared filtration.
- Check the species against your aquarium in TankWise before purchase.
Freshwater Angelfish
Pterophyllum scalare
What to notice
Review these species-specific points together: Pinched forehead, clamped fins, gill rate, bullying or submissive hiding.
Confirm that territorial display, pair or group dynamics, mouthbrooding where relevant, and persistent bullying are clearly separated.
White Cloud Mountain Minnow
Tanichthys albonubes
What to notice
Review these species-specific points together: Straight spine, full belly, clear fins, heat stress.
Confirm that schooling, chasing, colour change, and social position are explained without treating every shy or subordinate fish as ill.
Chili Rasbora
Boraras brigittae
What to notice
Review these species-specific points together: Tiny but rounded body, strong color, intact fins, confident group behavior.
Confirm that schooling, chasing, colour change, and social position are explained without treating every shy or subordinate fish as ill.
Glass Catfish
Kryptopterus vitreolus
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What to notice
Review these species-specific points together: Clear body without opaque patches, intact barbels, schooling, feeding response.
Confirm that resting, hiding, bottom-feeding, nocturnal activity, barbel condition, and breathing behaviour are described in a species-appropriate way.
Threadfin Rainbowfish
Iriatherina werneri
What to notice
Review these species-specific points together: Delicate fin rays, full belly, feeding response, fin-nipping tankmates.
Confirm that schooling, chasing, colour change, and social position are explained without treating every shy or subordinate fish as ill.
Ryukin Goldfish
Carassius auratus
Review these species-specific points together: Symmetrical hump and body, buoyancy, fin condition, clear gills.
Confirm that variety-specific body shape is not confused with deformity and that swimming balance, scale position, fins, eyes, and specialised features are checked.
Gold Laser Corydoras
Corydoras sp. CW010
Review these species-specific points together: Correct identity, belly condition, barbels, cohesive group behavior.
Confirm that resting, hiding, bottom-feeding, nocturnal activity, barbel condition, and breathing behaviour are described in a species-appropriate way.
Demasoni Cichlid
Chindongo demasoni
What to notice
Review these species-specific points together: Sunken belly, torn fins, correct identity, intense group aggression.
Confirm that territorial display, pair or group dynamics, mouthbrooding where relevant, and persistent bullying are clearly separated.
Banjo Catfish
Bunocephalus coracoideus
Review these species-specific points together: Full body, intact barbels, clean skin, normal camouflage and feeding response.
Confirm that resting, hiding, bottom-feeding, nocturnal activity, barbel condition, and breathing behaviour are described in a species-appropriate way.
Rainbow Shiner
Notropis chrosomus
What to notice
Review these species-specific points together: Scale and mouth damage, full body, cool-water stress, schooling.
Confirm that schooling, chasing, colour change, and social position are explained without treating every shy or subordinate fish as ill.
Sources and further reading
These references provide scientific or technical background and disclose how TankWise works. External references do not imply that every current TankWise catalog value was sourced from, or reviewed by, those organizations. See the checker methodology and known limits for that distinction.
- Selection of FishMerck Veterinary Manual
Veterinary-reviewed guidance on assessing a fish, its environment, skin, fins, eyes, movement, and alertness before purchase.
- Selecting a FishAmerican Veterinary Medical Association
Supports checking adult needs, body condition, breathing, behavior, and the wider sales system, while recognizing that a normal-looking fish may still carry disease.
- Pet Fish HealthRSPCA
Species-aware health context for appetite, breathing, alertness, eyes, fins, scales, and swimming.
- FishBase Species SearchFishBase
Scientific identity, distribution, biology, size, and cited species information used alongside other qualified sources.
- TankWise checker methodology and known limitsSimply Submerged Aquatics
The inputs, rules, safety limits, and uncertainty boundaries behind the TankWise aquarium comparison.
- Freshwater Angelfish species recordFishBase
Species reference for Freshwater Angelfish (Pterophyllum scalare).
- White Cloud Mountain Minnow species recordFishBase
Species reference for White Cloud Mountain Minnow (Tanichthys albonubes).
- Chili Rasbora species recordFishBase
Species reference for Chili Rasbora (Boraras brigittae).
- Glass Catfish species recordFishBase
Species reference for Glass Catfish (Kryptopterus vitreolus).
- Threadfin Rainbowfish species recordFishBase
Species reference for Threadfin Rainbowfish (Iriatherina werneri).
- Ryukin Goldfish species recordFishBase
Species reference for Ryukin Goldfish (Carassius auratus).
- Gold Laser Corydoras species recordFishBase
Species reference for Gold Laser Corydoras (Corydoras sp. CW010).
- Demasoni Cichlid species recordFishBase
Species reference for Demasoni Cichlid (Chindongo demasoni).
- Banjo Catfish species recordFishBase
Species reference for Banjo Catfish (Bunocephalus coracoideus).
- Rainbow Shiner species recordFishBase
Species reference for Rainbow Shiner (Notropis chrosomus).
Frequently asked questions
Can a fish that looks healthy still carry disease?
Yes. Visual screening can identify reasons to pause, but it cannot prove that a fish is free of pathogens or parasites. Quarantine new arrivals and avoid sharing wet equipment with an established aquarium.
Should I buy from a tank containing a dead or visibly distressed fish?
Pause and ask what happened, whether the tanks share filtration, and what action the retailer is taking. Choosing another fish from the same water does not remove shared exposure.
Is unusual color, hiding, or resting always a sign of illness?
No. Lighting, transport, age, sex, social position, and species-normal behavior can change appearance and activity. Review breathing, posture, body condition, skin, fins, eyes, and the condition of the whole tank together.
Why does this guide include 10 fish rather than ten?
Only fish with a licensed live or submerged exact-species reference photograph were included. Fish awaiting suitable photography remain unpublished instead of being represented by stock or substitute species.
Where does TankWise fit?
This guide helps screen the individual fish. TankWise then compares the species' needs with your aquarium, water, and current livestock. It does not diagnose illness or guarantee compatibility.