How to Choose Healthy Betta, Goldfish & 8 More Aquarium Fish

What to notice

A Betta may pause on a leaf, take air from the surface, or flare briefly at a neighbor or reflection. Those behaviors can be normal. The useful question is whether the fish can right itself, move through the water without obvious effort, respond to its surroundings, and settle again without persistent distress.

Judge fin condition against the variety. A crowntail has deliberately reduced webbing, while a long-finned male naturally moves differently from a short-finned plakat. Look for intact, consistent edges rather than assuming every uneven outline is damage.

What to notice

Common and comet Goldfish should have the streamlined body and single tail expected for their type. Juveniles are often sold very small, so condition at purchase must be separated from the substantial space, filtration, and adult-size plan they will need later.

A strong candidate swims level, turns cleanly, and can rise and descend without rolling. Brief bottom foraging is normal. Continuous floating, sinking, spinning, or exhaustion is not something to dismiss as a quirky Goldfish habit.

What to notice

A healthy Glowlight Tetra usually makes more sense in the group than alone. Watch for coordinated, responsive swimming and individuals that rejoin the school after investigating. Lighting, background, stress, age, and sex can affect color, so the orange stripe is useful context but not a stand-alone health test.

Small tetras can lose condition quietly. Look along the back and belly line for a full but not swollen profile, and compare the thinnest fish with several tankmates before choosing.

What to notice

Clown Plecos are built to cling, graze, and shelter around wood and cover. Hiding under bright store lights can be normal, so ask staff to help you see the underside, mouth, belly, and both eyes rather than judging inactivity alone.

Body condition matters especially in a recently shipped pleco. The abdomen should not look sharply caved in, and the sucker mouth should appear intact. Confirm the scientific name and expected adult size because a generic 'pleco' label is not specific enough for long-term planning.

What to notice

Odessa Barbs are active group fish. Mature males may show the famous red stripe strongly, while females and younger fish can be much plainer. Do not reject a healthy female because she lacks male display color, and do not let a vivid male's color distract from damaged fins or poor body condition.

Some chasing and display can be normal in a lively group. Focus on whether every fish can rejoin the group, feed, and use the aquarium without being continuously pinned, bitten, or exhausted.

What to notice

Weather Loaches are elongated, bottom-oriented fish with conspicuous barbels. They may burrow, become active with pressure changes, and take atmospheric air. A single trip to the surface is therefore different from continuous respiratory distress, especially when the fish otherwise explores, rests normally, and holds good condition.

Inspect every barbel and the smooth body surface closely. This is a cool-water species that can become large, and it is documented as nonindigenous in parts of the United States. Check current local sale and possession rules, plan a secure covered aquarium, and never release an aquarium animal outdoors.

What to notice

Flowerhorns are ornamental hybrid cichlids selected into many lines. Head-hump size, body shape, markings, and color vary widely, so a seller's grade is not the same as a health assessment. Look for functional swimming, a mouth that closes, clear eyes, intact fins, and skin without erosion.

A confident response to a person can be normal, as can intense territorial behavior. Aggression becomes a welfare issue when the fish is repeatedly injuring its mouth or head against glass, decorations, dividers, or tankmates.

What to notice

Electric Yellow Labs are Lake Malawi cichlids, and yellow tone or black fin edging can vary with age, sex, line, lighting, and condition. Judge color alongside body fullness, breathing, mouth condition, and how the fish moves through rockwork and the social group.

This species is a mouthbrooder. A female carrying eggs or fry may have an enlarged throat, hide more, and refuse food. That can be normal reproductive behavior, but the store should be able to explain it; do not assume mouthbrooding when the fish also has rapid breathing, poor posture, sores, or severe weight loss.

What to notice

Dwarf Synodontis are rock-associated catfish that may retreat from bright light and shelter under ledges. Ask to observe them in a shaded area or during feeding rather than treating hiding as proof of illness. The belly, barbels, eyes, skin, and fin edges should still be inspected.

The trade name 'dwarf Synodontis' is used loosely. Confirm the scientific name on the invoice or stock list and check the expected adult size; closely related Tanganyikan Synodontis can be difficult to distinguish in a quick store view.

What to notice

Despite its trade name, the Emerald Dwarf Rasbora is currently placed in the genus Danio. These tiny group fish can look pale in a bright or exposed store tank, and mature males may show stronger bars and orange-red fins than females. Compare several fish instead of selecting by color alone.

Because the species is small, a hollow belly, curved spine, rapid breathing, or inability to compete at feeding can be easy to miss. Watch the group long enough to see individuals rejoin, hold position, and take appropriately sized food.